802 Commits

Author SHA1 Message Date
Linus Torvalds
f21f7b5162 Merge tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull vdso updates from Thomas Gleixner:

 - Make the handling of compat functions consistent and more robust

 - Rework the underlying data store so that it is dynamically allocated,
   which allows the conversion of the last holdout SPARC64 to the
   generic VDSO implementation

 - Rework the SPARC64 VDSO to utilize the generic implementation

 - Mop up the left overs of the non-generic VDSO support in the core
   code

 - Expand the VDSO selftest and make them more robust

 - Allow time namespaces to be enabled independently of the generic VDSO
   support, which was not possible before due to SPARC64 not using it

 - Various cleanups and improvements in the related code

* tag 'timers-vdso-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits)
  timens: Use task_lock guard in timens_get*()
  timens: Use mutex guard in proc_timens_set_offset()
  timens: Simplify some calls to put_time_ns()
  timens: Add a __free() wrapper for put_time_ns()
  timens: Remove dependency on the vDSO
  vdso/timens: Move functions to new file
  selftests: vDSO: vdso_test_correctness: Add a test for time()
  selftests: vDSO: vdso_test_correctness: Use facilities from parse_vdso.c
  selftests: vDSO: vdso_test_correctness: Handle different tv_usec types
  selftests: vDSO: vdso_test_correctness: Drop SYS_getcpu fallbacks
  selftests: vDSO: vdso_test_gettimeofday: Remove nolibc checks
  Revert "selftests: vDSO: parse_vdso: Use UAPI headers instead of libc headers"
  random: vDSO: Remove ifdeffery
  random: vDSO: Trim vDSO includes
  vdso/datapage: Trim down unnecessary includes
  vdso/datapage: Remove inclusion of gettimeofday.h
  vdso/helpers: Explicitly include vdso/processor.h
  vdso/gettimeofday: Add explicit includes
  random: vDSO: Add explicit includes
  MIPS: vdso: Explicitly include asm/vdso/vdso.h
  ...
2026-04-14 10:53:44 -07:00
Linus Torvalds
4793dae01f Merge tag 'driver-core-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core
Pull driver core updates from Danilo Krummrich:
 "debugfs:
   - Fix NULL pointer dereference in debugfs_create_str()
   - Fix misplaced EXPORT_SYMBOL_GPL for debugfs_create_str()
   - Fix soundwire debugfs NULL pointer dereference from uninitialized
     firmware_file

  device property:
   - Make fwnode flags modifications thread safe; widen the field to
     unsigned long and use set_bit() / clear_bit() based accessors
   - Document how to check for the property presence

  devres:
   - Separate struct devres_node from its "subclasses" (struct devres,
     struct devres_group); give struct devres_node its own release and
     free callbacks for per-type dispatch
   - Introduce struct devres_action for devres actions, avoiding the
     ARCH_DMA_MINALIGN alignment overhead of struct devres
   - Export struct devres_node and its init/add/remove/dbginfo
     primitives for use by Rust Devres<T>
   - Fix missing node debug info in devm_krealloc()
   - Use guard(spinlock_irqsave) where applicable; consolidate unlock
     paths in devres_release_group()

  driver_override:
   - Convert PCI, WMI, vdpa, s390/cio, s390/ap, and fsl-mc to the
     generic driver_override infrastructure, replacing per-bus
     driver_override strings, sysfs attributes, and match logic; fixes a
     potential UAF from unsynchronized access to driver_override in bus
     match() callbacks
   - Simplify __device_set_driver_override() logic

  kernfs:
   - Send IN_DELETE_SELF and IN_IGNORED inotify events on kernfs file
     and directory removal
   - Add corresponding selftests for memcg

  platform:
   - Allow attaching software nodes when creating platform devices via a
     new 'swnode' field in struct platform_device_info
   - Add kerneldoc for struct platform_device_info

  software node:
   - Move software node initialization from postcore_initcall() to
     driver_init(), making it available early in the boot process
   - Move kernel_kobj initialization (ksysfs_init) earlier to support
     the above
   - Remove software_node_exit(); dead code in a built-in unit

  SoC:
   - Introduce of_machine_read_compatible() and of_machine_read_model()
     OF helpers and export soc_attr_read_machine() to replace direct
     accesses to of_root from SoC drivers; also enables
     CONFIG_COMPILE_TEST coverage for these drivers

  sysfs:
   - Constify attribute group array pointers to
     'const struct attribute_group *const *' in sysfs functions,
     device_add_groups() / device_remove_groups(), and struct class

  Rust:
   - Devres:
      - Embed struct devres_node directly in Devres<T> instead of going
        through devm_add_action(), avoiding the extra allocation and the
        unnecessary ARCH_DMA_MINALIGN alignment

   - I/O:
      - Turn IoCapable from a marker trait into a functional trait
        carrying the raw I/O accessor implementation (io_read /
        io_write), providing working defaults for the per-type Io
        methods
      - Add RelaxedMmio wrapper type, making relaxed accessors usable in
        code generic over the Io trait
      - Remove overloaded per-type Io methods and per-backend macros
        from Mmio and PCI ConfigSpace

   - I/O (Register):
      - Add IoLoc trait and generic read/write/update methods to the Io
        trait, making I/O operations parameterizable by typed locations
      - Add register! macro for defining hardware register types with
        typed bitfield accessors backed by Bounded values; supports
        direct, relative, and array register addressing
      - Add write_reg() / try_write_reg() and LocatedRegister trait
      - Update PCI sample driver to demonstrate the register! macro

         Example:

         ```
             register! {
                 /// UART control register.
                 CTRL(u32) @ 0x18 {
                     /// Receiver enable.
                     19:19   rx_enable => bool;
                     /// Parity configuration.
                     14:13   parity ?=> Parity;
                 }

                 /// FIFO watermark and counter register.
                 WATER(u32) @ 0x2c {
                     /// Number of datawords in the receive FIFO.
                     26:24   rx_count;
                     /// RX interrupt threshold.
                     17:16   rx_water;
                 }
             }

             impl WATER {
                 fn rx_above_watermark(&self) -> bool {
                     self.rx_count() > self.rx_water()
                 }
             }

             fn init(bar: &pci::Bar<BAR0_SIZE>) {
                 let water = WATER::zeroed()
                     .with_const_rx_water::<1>(); // > 3 would not compile
                 bar.write_reg(water);

                 let ctrl = CTRL::zeroed()
                     .with_parity(Parity::Even)
                     .with_rx_enable(true);
                 bar.write_reg(ctrl);
             }

             fn handle_rx(bar: &pci::Bar<BAR0_SIZE>) {
                 if bar.read(WATER).rx_above_watermark() {
                     // drain the FIFO
                 }
             }

             fn set_parity(bar: &pci::Bar<BAR0_SIZE>, parity: Parity) {
                 bar.update(CTRL, |r| r.with_parity(parity));
             }
         ```

   - IRQ:
      - Move 'static bounds from where clauses to trait declarations for
        IRQ handler traits

   - Misc:
      - Enable the generic_arg_infer Rust feature
      - Extend Bounded with shift operations, single-bit bool
        conversion, and const get()

  Misc:
   - Make deferred_probe_timeout default a Kconfig option
   - Drop auxiliary_dev_pm_ops; the PM core falls back to driver PM
     callbacks when no bus type PM ops are set
   - Add conditional guard support for device_lock()
   - Add ksysfs.c to the DRIVER CORE MAINTAINERS entry
   - Fix kernel-doc warnings in base.h
   - Fix stale reference to memory_block_add_nid() in documentation"

* tag 'driver-core-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core: (67 commits)
  bus: fsl-mc: use generic driver_override infrastructure
  s390/ap: use generic driver_override infrastructure
  s390/cio: use generic driver_override infrastructure
  vdpa: use generic driver_override infrastructure
  platform/wmi: use generic driver_override infrastructure
  PCI: use generic driver_override infrastructure
  driver core: make software nodes available earlier
  software node: remove software_node_exit()
  kernel: ksysfs: initialize kernel_kobj earlier
  MAINTAINERS: add ksysfs.c to the DRIVER CORE entry
  drivers/base/memory: fix stale reference to memory_block_add_nid()
  device property: Document how to check for the property presence
  soundwire: debugfs: initialize firmware_file to empty string
  debugfs: fix placement of EXPORT_SYMBOL_GPL for debugfs_create_str()
  debugfs: check for NULL pointer in debugfs_create_str()
  driver core: Make deferred_probe_timeout default a Kconfig option
  driver core: simplify __device_set_driver_override() clearing logic
  driver core: auxiliary bus: Drop auxiliary_dev_pm_ops
  device property: Make modifications of fwnode "flags" thread safe
  rust: devres: embed struct devres_node directly
  ...
2026-04-13 19:03:11 -07:00
Bartosz Golaszewski
9617b5b62c kernel: ksysfs: initialize kernel_kobj earlier
Software nodes depend on kernel_kobj which is initialized pretty late
into the boot process - as a core_initcall(). Ahead of moving the
software node initialization to driver_init() we must first make
kernel_kobj available before it.

Make ksysfs_init() visible in a new header - ksysfs.h - and call it in
do_basic_setup() right before driver_init().

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260402-nokia770-gpio-swnodes-v5-1-d730db3dd299@oss.qualcomm.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2026-04-03 19:39:52 +02:00
Ryan Roberts
a96ef5848c randomize_kstack: Unify random source across arches
Previously different architectures were using random sources of
differing strength and cost to decide the random kstack offset. A number
of architectures (loongarch, powerpc, s390, x86) were using their
timestamp counter, at whatever the frequency happened to be. Other
arches (arm64, riscv) were using entropy from the crng via
get_random_u16().

There have been concerns that in some cases the timestamp counters may
be too weak, because they can be easily guessed or influenced by user
space. And get_random_u16() has been shown to be too costly for the
level of protection kstack offset randomization provides.

So let's use a common, architecture-agnostic source of entropy; a
per-cpu prng, seeded at boot-time from the crng. This has a few
benefits:

  - We can remove choose_random_kstack_offset(); That was only there to
    try to make the timestamp counter value a bit harder to influence
    from user space [*].

  - The architecture code is simplified. All it has to do now is call
    add_random_kstack_offset() in the syscall path.

  - The strength of the randomness can be reasoned about independently
    of the architecture.

  - Arches previously using get_random_u16() now have much faster
    syscall paths, see below results.

[*] Additionally, this gets rid of some redundant work on s390 and x86.
Before this patch, those architectures called
choose_random_kstack_offset() under arch_exit_to_user_mode_prepare(),
which is also called for exception returns to userspace which were *not*
syscalls (e.g. regular interrupts). Getting rid of
choose_random_kstack_offset() avoids a small amount of redundant work
for the non-syscall cases.

In some configurations, add_random_kstack_offset() will now call
instrumentable code, so for a couple of arches, I have moved the call a
bit later to the first point where instrumentation is allowed. This
doesn't impact the efficacy of the mechanism.

There have been some claims that a prng may be less strong than the
timestamp counter if not regularly reseeded. But the prng has a period
of about 2^113. So as long as the prng state remains secret, it should
not be possible to guess. If the prng state can be accessed, we have
bigger problems.

Additionally, we are only consuming 6 bits to randomize the stack, so
there are only 64 possible random offsets. I assert that it would be
trivial for an attacker to brute force by repeating their attack and
waiting for the random stack offset to be the desired one. The prng
approach seems entirely proportional to this level of protection.

Performance data are provided below. The baseline is v6.18 with rndstack
on for each respective arch. (I)/(R) indicate statistically significant
improvement/regression. arm64 platform is AWS Graviton3 (m7g.metal).
x86_64 platform is AWS Sapphire Rapids (m7i.24xlarge):

+-----------------+--------------+---------------+---------------+
| Benchmark       | Result Class |  per-cpu-prng |  per-cpu-prng |
|                 |              | arm64 (metal) |   x86_64 (VM) |
+=================+==============+===============+===============+
| syscall/getpid  | mean (ns)    |    (I) -9.50% |   (I) -17.65% |
|                 | p99 (ns)     |   (I) -59.24% |   (I) -24.41% |
|                 | p99.9 (ns)   |   (I) -59.52% |   (I) -28.52% |
+-----------------+--------------+---------------+---------------+
| syscall/getppid | mean (ns)    |    (I) -9.52% |   (I) -19.24% |
|                 | p99 (ns)     |   (I) -59.25% |   (I) -25.03% |
|                 | p99.9 (ns)   |   (I) -59.50% |   (I) -28.17% |
+-----------------+--------------+---------------+---------------+
| syscall/invalid | mean (ns)    |   (I) -10.31% |   (I) -18.56% |
|                 | p99 (ns)     |   (I) -60.79% |   (I) -20.06% |
|                 | p99.9 (ns)   |   (I) -61.04% |   (I) -25.04% |
+-----------------+--------------+---------------+---------------+

I tested an earlier version of this change on x86 bare metal and it
showed a smaller but still significant improvement. The bare metal
system wasn't available this time around so testing was done in a VM
instance. I'm guessing the cost of rdtsc is higher for VMs.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Link: https://patch.msgid.link/20260303150840.3789438-3-ryan.roberts@arm.com
Signed-off-by: Kees Cook <kees@kernel.org>
2026-03-24 21:12:03 -07:00
Ryan Roberts
37beb42560 randomize_kstack: Maintain kstack_offset per task
kstack_offset was previously maintained per-cpu, but this caused a
couple of issues. So let's instead make it per-task.

Issue 1: add_random_kstack_offset() and choose_random_kstack_offset()
expected and required to be called with interrupts and preemption
disabled so that it could manipulate per-cpu state. But arm64, loongarch
and risc-v are calling them with interrupts and preemption enabled. I
don't _think_ this causes any functional issues, but it's certainly
unexpected and could lead to manipulating the wrong cpu's state, which
could cause a minor performance degradation due to bouncing the cache
lines. By maintaining the state per-task those functions can safely be
called in preemptible context.

Issue 2: add_random_kstack_offset() is called before executing the
syscall and expands the stack using a previously chosen random offset.
choose_random_kstack_offset() is called after executing the syscall and
chooses and stores a new random offset for the next syscall. With
per-cpu storage for this offset, an attacker could force cpu migration
during the execution of the syscall and prevent the offset from being
updated for the original cpu such that it is predictable for the next
syscall on that cpu. By maintaining the state per-task, this problem
goes away because the per-task random offset is updated after the
syscall regardless of which cpu it is executing on.

Fixes: 39218ff4c6 ("stack: Optionally randomize kernel stack offset each syscall")
Closes: https://lore.kernel.org/all/dd8c37bc-795f-4c7a-9086-69e584d8ab24@arm.com/
Cc: stable@vger.kernel.org
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Link: https://patch.msgid.link/20260303150840.3789438-2-ryan.roberts@arm.com
Signed-off-by: Kees Cook <kees@kernel.org>
2026-03-24 21:12:03 -07:00
Thomas Weißschuh
05988dba11 vdso/datastore: Allocate data pages dynamically
Allocating the data pages as part of the kernel image does not work on
SPARC. The MMU will raise a fault when userspace tries to access them.

Allocate the data pages through the page allocator instead.

Unused pages in the vDSO VMA are still allocated to keep the virtual
addresses aligned. Switch the mapping from PFNs to 'struct page' as that is
required for dynamically allocated pages.  This also aligns the allocation
of the datapages with the code pages and is a prerequisite for mlockall()
support.

VM_MIXEDMAP is necessary for the call to vmf_insert_page() in the timens
prefault path to work.

The data pages need to be order-0, non-compound pages so that the mapping
to userspace and the different orderings work.

These pages are also used by the timekeeping, random pool and architecture
initialization code. Some of these are running before the page allocator is
available. To keep these subsytems working without changes, introduce
early, statically data storage which will then replaced by the real one as
soon as that is available.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Link: https://patch.msgid.link/20260304-vdso-sparc64-generic-2-v6-3-d8eb3b0e1410@linutronix.de
2026-03-11 10:18:30 +01:00
Linus Torvalds
136114e0ab Merge tag 'mm-nonmm-stable-2026-02-12-10-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:

 - "ocfs2: give ocfs2 the ability to reclaim suballocator free bg" saves
   disk space by teaching ocfs2 to reclaim suballocator block group
   space (Heming Zhao)

 - "Add ARRAY_END(), and use it to fix off-by-one bugs" adds the
   ARRAY_END() macro and uses it in various places (Alejandro Colomar)

 - "vmcoreinfo: support VMCOREINFO_BYTES larger than PAGE_SIZE" makes
   the vmcore code future-safe, if VMCOREINFO_BYTES ever exceeds the
   page size (Pnina Feder)

 - "kallsyms: Prevent invalid access when showing module buildid" cleans
   up kallsyms code related to module buildid and fixes an invalid
   access crash when printing backtraces (Petr Mladek)

 - "Address page fault in ima_restore_measurement_list()" fixes a
   kexec-related crash that can occur when booting the second-stage
   kernel on x86 (Harshit Mogalapalli)

 - "kho: ABI headers and Documentation updates" updates the kexec
   handover ABI documentation (Mike Rapoport)

 - "Align atomic storage" adds the __aligned attribute to atomic_t and
   atomic64_t definitions to get natural alignment of both types on
   csky, m68k, microblaze, nios2, openrisc and sh (Finn Thain)

 - "kho: clean up page initialization logic" simplifies the page
   initialization logic in kho_restore_page() (Pratyush Yadav)

 - "Unload linux/kernel.h" moves several things out of kernel.h and into
   more appropriate places (Yury Norov)

 - "don't abuse task_struct.group_leader" removes the usage of
   ->group_leader when it is "obviously unnecessary" (Oleg Nesterov)

 - "list private v2 & luo flb" adds some infrastructure improvements to
   the live update orchestrator (Pasha Tatashin)

* tag 'mm-nonmm-stable-2026-02-12-10-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (107 commits)
  watchdog/hardlockup: simplify perf event probe and remove per-cpu dependency
  procfs: fix missing RCU protection when reading real_parent in do_task_stat()
  watchdog/softlockup: fix sample ring index wrap in need_counting_irqs()
  kcsan, compiler_types: avoid duplicate type issues in BPF Type Format
  kho: fix doc for kho_restore_pages()
  tests/liveupdate: add in-kernel liveupdate test
  liveupdate: luo_flb: introduce File-Lifecycle-Bound global state
  liveupdate: luo_file: Use private list
  list: add kunit test for private list primitives
  list: add primitives for private list manipulations
  delayacct: fix uapi timespec64 definition
  panic: add panic_force_cpu= parameter to redirect panic to a specific CPU
  netclassid: use thread_group_leader(p) in update_classid_task()
  RDMA/umem: don't abuse current->group_leader
  drm/pan*: don't abuse current->group_leader
  drm/amd: kill the outdated "Only the pthreads threading model is supported" checks
  drm/amdgpu: don't abuse current->group_leader
  android/binder: use same_thread_group(proc->tsk, current) in binder_mmap()
  android/binder: don't abuse current->group_leader
  kho: skip memoryless NUMA nodes when reserving scratch areas
  ...
2026-02-12 12:13:01 -08:00
Mike Rapoport (Microsoft)
d49004c5f0 arch, mm: consolidate initialization of nodes, zones and memory map
To initialize node, zone and memory map data structures every architecture
calls free_area_init() during setup_arch() and passes it an array of zone
limits.

Beside code duplication it creates "interesting" ordering cases between
allocation and initialization of hugetlb and the memory map.  Some
architectures allocate hugetlb pages very early in setup_arch() in certain
cases, some only create hugetlb CMA areas in setup_arch() and sometimes
hugetlb allocations happen mm_core_init().

With arch_zone_limits_init() helper available now on all architectures it
is no longer necessary to call free_area_init() from architecture setup
code.  Rather core MM initialization can call arch_zone_limits_init() in a
single place.

This allows to unify ordering of hugetlb vs memory map allocation and
initialization.

Remove the call to free_area_init() from architecture specific code and
place it in a new mm_core_init_early() function that is called immediately
after setup_arch().

After this refactoring it is possible to consolidate hugetlb allocations
and eliminate differences in ordering of hugetlb and memory map
initialization among different architectures.

As the first step of this consolidation move hugetlb_bootmem_alloc() to
mm_core_early_init().

Link: https://lkml.kernel.org/r/20260111082105.290734-24-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Pratyush Yadav <pratyush@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26 20:02:18 -08:00
Sun Jian
499f86de4f init/main: read bootconfig header with get_unaligned_le32()
get_boot_config_from_initrd() scans up to 3 bytes before initrd_end to
handle GRUB 4-byte alignment.  As a result, the bootconfig header
immediately preceding the magic may be unaligned.

Read the size and checksum fields with get_unaligned_le32() instead of
casting to u32 * and using le32_to_cpu(), avoiding potential unaligned
access and silencing sparse "cast to restricted __le32" warnings.

Sparse warnings (gcc + C=1):
  init/main.c:292:16: warning: cast to restricted __le32
  init/main.c:293:16: warning: cast to restricted __le32

No functional change intended.

Link: https://lkml.kernel.org/r/20260113101532.1630770-1-sun.jian.kdev@gmail.com
Signed-off-by: Sun Jian <sun.jian.kdev@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26 19:07:14 -08:00
Lillian Berry
a906f3ae44 init/main.c: check if rdinit was explicitly set before printing warning
The rdinit parameter is set by default, and attempted during boot even if
not specified in the command line.  Only print the warning about rdinit
being inaccessible if the rdinit value was found in command line; it's
just noise otherwise.

[akpm@linux-foundation.org: move ramdisk_execute_command_set into __initdata]
Link: https://lkml.kernel.org/r/20260111125635.53682-1-lillian@star-ark.net
Signed-off-by: Lillian Berry <lillian@star-ark.net>
Cc: Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Francesco Valla <francesco@valla.it>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Huan Yang <link@vivo.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26 19:07:14 -08:00
Douglas Anderson
032a730268 init/main.c: wrap long kernel cmdline when printing to logs
The kernel cmdline length is allowed to be longer than what printk can
handle.  When this happens the cmdline that's printed to the kernel ring
buffer at bootup is cutoff and some kernel cmdline options are "hidden"
from the logs.  This undercuts the usefulness of the log message.

Specifically, grepping for COMMAND_LINE_SIZE shows that 2048 is common and
some architectures even define it as 4096.  s390 allows a CONFIG-based
maximum up to 1MB (though it's not expected that anyone will go over the
default max of 4096 [1]).

The maximum message pr_notice() seems to be able to handle (based on
experiment) is 1021 characters.  This appears to be based on the current
value of PRINTKRB_RECORD_MAX as 1024 and the fact that pr_notice() spends
2 characters on the loglevel prefix and we have a '\n' at the end.

While it would be possible to increase the limits of printk() (and
therefore pr_notice()) somewhat, it doesn't appear possible to increase it
enough to fully include a 2048-character cmdline without breaking
userspace.  Specifically on at least two tested userspaces (ChromeOS plus
the Debian-based distro I'm typing this message on) the `dmesg` tool reads
lines from `/dev/kmsg` in 2047-byte chunks.  As per
`Documentation/ABI/testing/dev-kmsg`:

  Every read() from the opened device node receives one record
  of the kernel's printk buffer.
  ...
  Messages in the record ring buffer get overwritten as whole,
  there are never partial messages received by read().

We simply can't fit a 2048-byte cmdline plus the "Kernel command line:"
prefix plus info about time/log_level/etc in a 2047-byte read.

The above means that if we want to avoid the truncation we need to do some
type of wrapping of the cmdline when printing.

Add wrapping to the printout of the kernel command line.  By default, the
wrapping is set to 1021 characters to avoid breaking anyone, but allow
wrapping to be set lower by a Kconfig knob
"CONFIG_CMDLINE_LOG_WRAP_IDEAL_LEN".  Any tools that are correctly parsing
the cmdline today (because it is less than 1021 characters) will see no
difference in their behavior.  The format of wrapped output is designed to
be matched by anyone using "grep" to search for the cmdline and also to be
easy for tools to handle.  Anyone who is sure their tools (if any) handle
the wrapped format can choose a lower wrapping value and have prettier
output.

Setting CONFIG_CMDLINE_LOG_WRAP_IDEAL_LEN to 0 fully disables the wrapping
logic.  This means that long command lines will be truncated again, but
this config could be set if command lines are expected to be long and
userspace is known not to handle parsing logs with the wrapping.

Wrapping is based on spaces, ignoring quotes.  All lines are prefixed with
"Kernel command line: " and lines that are not the last line have a " \"
suffix added to them.  The prefix and suffix count towards the line length
for wrapping purposes.  The ideal length will be exceeded if no
appropriate place to wrap is found.

The wrapping function added here is fairly generic and could be made a
library function (somewhat like print_hex_dump()) if it's needed elsewhere
in the kernel.  However, having printk() directly incorporate this
wrapping would be unlikely to be a good idea since it would break
printouts into more than one record without any obvious common line prefix
to tie lines together.  It would also be extra overhead when, in general,
kernel log message should simply be kept smaller than 1021 bytes.  For
some discussion on this topic, see responses to the v1 posting of this
patch [2].

[akpm@linux-foundation.org: make print_kernel_cmdline __init]
[dianders@chromium.org: v4]
  Link: https://lkml.kernel.org/r/20251027082204.v4.1.I095f1e2c6c27f9f4de0b4841f725f356c643a13f@changeid
Link: https://lkml.kernel.org/r/20251023113257.v3.1.I095f1e2c6c27f9f4de0b4841f725f356c643a13f@changeid
Link: https://lore.kernel.org/r/20251021131633.26700Dd6-hca@linux.ibm.com [1]
Link: https://lore.kernel.org/r/CAD=FV=VNyt1zG_8pS64wgV8VkZWiWJymnZ-XCfkrfaAhhFSKcA@mail.gmail.com [2]
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Chant <achant@google.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Francesco Valla <francesco@valla.it>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: guoweikang <guoweikang.kernel@gmail.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Hendrik Farr <kernel@jfarr.cc>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-12 10:00:16 -08:00
Linus Torvalds
e406d57be7 Merge tag 'mm-nonmm-stable-2025-10-02-15-29' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:

 - "ida: Remove the ida_simple_xxx() API" from Christophe Jaillet
   completes the removal of this legacy IDR API

 - "panic: introduce panic status function family" from Jinchao Wang
   provides a number of cleanups to the panic code and its various
   helpers, which were rather ad-hoc and scattered all over the place

 - "tools/delaytop: implement real-time keyboard interaction support"
   from Fan Yu adds a few nice user-facing usability changes to the
   delaytop monitoring tool

 - "efi: Fix EFI boot with kexec handover (KHO)" from Evangelos
   Petrongonas fixes a panic which was happening with the combination of
   EFI and KHO

 - "Squashfs: performance improvement and a sanity check" from Phillip
   Lougher teaches squashfs's lseek() about SEEK_DATA/SEEK_HOLE. A mere
   150x speedup was measured for a well-chosen microbenchmark

 - plus another 50-odd singleton patches all over the place

* tag 'mm-nonmm-stable-2025-10-02-15-29' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (75 commits)
  Squashfs: reject negative file sizes in squashfs_read_inode()
  kallsyms: use kmalloc_array() instead of kmalloc()
  MAINTAINERS: update Sibi Sankar's email address
  Squashfs: add SEEK_DATA/SEEK_HOLE support
  Squashfs: add additional inode sanity checking
  lib/genalloc: fix device leak in of_gen_pool_get()
  panic: remove CONFIG_PANIC_ON_OOPS_VALUE
  ocfs2: fix double free in user_cluster_connect()
  checkpatch: suppress strscpy warnings for userspace tools
  cramfs: fix incorrect physical page address calculation
  kernel: prevent prctl(PR_SET_PDEATHSIG) from racing with parent process exit
  Squashfs: fix uninit-value in squashfs_get_parent
  kho: only fill kimage if KHO is finalized
  ocfs2: avoid extra calls to strlen() after ocfs2_sprintf_system_inode_name()
  kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths
  sched/task.h: fix the wrong comment on task_lock() nesting with tasklist_lock
  coccinelle: platform_no_drv_owner: handle also built-in drivers
  coccinelle: of_table: handle SPI device ID tables
  lib/decompress: use designated initializers for struct compress_format
  efi: support booting with kexec handover (KHO)
  ...
2025-10-02 18:44:54 -07:00
Linus Torvalds
18b19abc37 Merge tag 'namespace-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull namespace updates from Christian Brauner:
 "This contains a larger set of changes around the generic namespace
  infrastructure of the kernel.

  Each specific namespace type (net, cgroup, mnt, ...) embedds a struct
  ns_common which carries the reference count of the namespace and so
  on.

  We open-coded and cargo-culted so many quirks for each namespace type
  that it just wasn't scalable anymore. So given there's a bunch of new
  changes coming in that area I've started cleaning all of this up.

  The core change is to make it possible to correctly initialize every
  namespace uniformly and derive the correct initialization settings
  from the type of the namespace such as namespace operations, namespace
  type and so on. This leaves the new ns_common_init() function with a
  single parameter which is the specific namespace type which derives
  the correct parameters statically. This also means the compiler will
  yell as soon as someone does something remotely fishy.

  The ns_common_init() addition also allows us to remove ns_alloc_inum()
  and drops any special-casing of the initial network namespace in the
  network namespace initialization code that Linus complained about.

  Another part is reworking the reference counting. The reference
  counting was open-coded and copy-pasted for each namespace type even
  though they all followed the same rules. This also removes all open
  accesses to the reference count and makes it private and only uses a
  very small set of dedicated helpers to manipulate them just like we do
  for e.g., files.

  In addition this generalizes the mount namespace iteration
  infrastructure introduced a few cycles ago. As reminder, the vfs makes
  it possible to iterate sequentially and bidirectionally through all
  mount namespaces on the system or all mount namespaces that the caller
  holds privilege over. This allow userspace to iterate over all mounts
  in all mount namespaces using the listmount() and statmount() system
  call.

  Each mount namespace has a unique identifier for the lifetime of the
  systems that is exposed to userspace. The network namespace also has a
  unique identifier working exactly the same way. This extends the
  concept to all other namespace types.

  The new nstree type makes it possible to lookup namespaces purely by
  their identifier and to walk the namespace list sequentially and
  bidirectionally for all namespace types, allowing userspace to iterate
  through all namespaces. Looking up namespaces in the namespace tree
  works completely locklessly.

  This also means we can move the mount namespace onto the generic
  infrastructure and remove a bunch of code and members from struct
  mnt_namespace itself.

  There's a bunch of stuff coming on top of this in the future but for
  now this uses the generic namespace tree to extend a concept
  introduced first for pidfs a few cycles ago. For a while now we have
  supported pidfs file handles for pidfds. This has proven to be very
  useful.

  This extends the concept to cover namespaces as well. It is possible
  to encode and decode namespace file handles using the common
  name_to_handle_at() and open_by_handle_at() apis.

  As with pidfs file handles, namespace file handles are exhaustive,
  meaning it is not required to actually hold a reference to nsfs in
  able to decode aka open_by_handle_at() a namespace file handle.
  Instead the FD_NSFS_ROOT constant can be passed which will let the
  kernel grab a reference to the root of nsfs internally and thus decode
  the file handle.

  Namespaces file descriptors can already be derived from pidfds which
  means they aren't subject to overmount protection bugs. IOW, it's
  irrelevant if the caller would not have access to an appropriate
  /proc/<pid>/ns/ directory as they could always just derive the
  namespace based on a pidfd already.

  It has the same advantage as pidfds. It's possible to reliably and for
  the lifetime of the system refer to a namespace without pinning any
  resources and to compare them trivially.

  Permission checking is kept simple. If the caller is located in the
  namespace the file handle refers to they are able to open it otherwise
  they must hold privilege over the owning namespace of the relevant
  namespace.

  The namespace file handle layout is exposed as uapi and has a stable
  and extensible format. For now it simply contains the namespace
  identifier, the namespace type, and the inode number. The stable
  format means that userspace may construct its own namespace file
  handles without going through name_to_handle_at() as they are already
  allowed for pidfs and cgroup file handles"

* tag 'namespace-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (65 commits)
  ns: drop assert
  ns: move ns type into struct ns_common
  nstree: make struct ns_tree private
  ns: add ns_debug()
  ns: simplify ns_common_init() further
  cgroup: add missing ns_common include
  ns: use inode initializer for initial namespaces
  selftests/namespaces: verify initial namespace inode numbers
  ns: rename to __ns_ref
  nsfs: port to ns_ref_*() helpers
  net: port to ns_ref_*() helpers
  uts: port to ns_ref_*() helpers
  ipv4: use check_net()
  net: use check_net()
  net-sysfs: use check_net()
  user: port to ns_ref_*() helpers
  time: port to ns_ref_*() helpers
  pid: port to ns_ref_*() helpers
  ipc: port to ns_ref_*() helpers
  cgroup: port to ns_ref_*() helpers
  ...
2025-09-29 11:20:29 -07:00
Christian Brauner
b36c823b9a time: support ns lookup
Support the generic ns lookup infrastructure to support file handles for
namespaces.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-09-19 14:26:15 +02:00
Huacai Chen
e416f0ed3c init: handle bootloader identifier in kernel parameters
BootLoaders (Grub, LILO, etc) may pass an identifier such as "BOOT_IMAGE=
/boot/vmlinuz-x.y.z" to kernel parameters.  But these identifiers are not
recognized by the kernel itself so will be passed to userspace.  However
user space init program also don't recognize it.

KEXEC/KDUMP (kexec-tools) may also pass an identifier such as "kexec" on
some architectures.

We cannot change BootLoader's behavior, because this behavior exists for
many years, and there are already user space programs search BOOT_IMAGE=
in /proc/cmdline to obtain the kernel image locations:

https://github.com/linuxdeepin/deepin-ab-recovery/blob/master/util.go
(search getBootOptions)
https://github.com/linuxdeepin/deepin-ab-recovery/blob/master/main.go
(search getKernelReleaseWithBootOption) So the the best way is handle
(ignore) it by the kernel itself, which can avoid such boot warnings (if
we use something like init=/bin/bash, bootloader identifier can even cause
a crash):

Kernel command line: BOOT_IMAGE=(hd0,1)/vmlinuz-6.x root=/dev/sda3 ro console=tty
Unknown kernel command line parameters "BOOT_IMAGE=(hd0,1)/vmlinuz-6.x", will be passed to user space.

[chenhuacai@loongson.cn: use strstarts()]
  Link: https://lkml.kernel.org/r/20250815090120.1569947-1-chenhuacai@loongson.cn
Link: https://lkml.kernel.org/r/20250721101343.3283480-1-chenhuacai@loongson.cn
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-13 17:32:45 -07:00
Mike Rapoport (Microsoft)
669602b5b7 init/main.c: fix boot time tracing crash
Steven Rostedt reported a crash with "ftrace=function" kernel command
line:

[    0.159269] BUG: kernel NULL pointer dereference, address: 000000000000001c
[    0.160254] #PF: supervisor read access in kernel mode
[    0.160975] #PF: error_code(0x0000) - not-present page
[    0.161697] PGD 0 P4D 0
[    0.162055] Oops: Oops: 0000 [#1] SMP PTI
[    0.162619] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.17.0-rc2-test-00006-g48d06e78b7cb-dirty #9 PREEMPT(undef)
[    0.164141] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[    0.165439] RIP: 0010:kmem_cache_alloc_noprof (mm/slub.c:4237)
[ 0.166186] Code: 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 49 89 fc 53 48 83 e4 f0 48 83 ec 20 8b 05 c9 b6 7e 01 <44> 8b 77 1c 65 4c 8b 2d b5 ea 20 02 4c 89 6c 24 18 41 89 f5 21 f0
[    0.168811] RSP: 0000:ffffffffb2e03b30 EFLAGS: 00010086
[    0.169545] RAX: 0000000001fff33f RBX: 0000000000000000 RCX: 0000000000000000
[    0.170544] RDX: 0000000000002800 RSI: 0000000000002800 RDI: 0000000000000000
[    0.171554] RBP: ffffffffb2e03b80 R08: 0000000000000004 R09: ffffffffb2e03c90
[    0.172549] R10: ffffffffb2e03c90 R11: 0000000000000000 R12: 0000000000000000
[    0.173544] R13: ffffffffb2e03c90 R14: ffffffffb2e03c90 R15: 0000000000000001
[    0.174542] FS:  0000000000000000(0000) GS:ffff9d2808114000(0000) knlGS:0000000000000000
[    0.175684] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    0.176486] CR2: 000000000000001c CR3: 000000007264c001 CR4: 00000000000200b0
[    0.177483] Call Trace:
[    0.177828]  <TASK>
[    0.178123] mas_alloc_nodes (lib/maple_tree.c:176 (discriminator 2) lib/maple_tree.c:1255 (discriminator 2))
[    0.178692] mas_store_gfp (lib/maple_tree.c:5468)
[    0.179223] execmem_cache_add_locked (mm/execmem.c:207)
[    0.179870] execmem_alloc (mm/execmem.c:213 mm/execmem.c:313 mm/execmem.c:335 mm/execmem.c:475)
[    0.180397] ? ftrace_caller (arch/x86/kernel/ftrace_64.S:169)
[    0.180922] ? __pfx_ftrace_caller (arch/x86/kernel/ftrace_64.S:158)
[    0.181517] execmem_alloc_rw (mm/execmem.c:487)
[    0.182052] arch_ftrace_update_trampoline (arch/x86/kernel/ftrace.c:266 arch/x86/kernel/ftrace.c:344 arch/x86/kernel/ftrace.c:474)
[    0.182778] ? ftrace_caller_op_ptr (arch/x86/kernel/ftrace_64.S:182)
[    0.183388] ftrace_update_trampoline (kernel/trace/ftrace.c:7947)
[    0.184024] __register_ftrace_function (kernel/trace/ftrace.c:368)
[    0.184682] ftrace_startup (kernel/trace/ftrace.c:3048)
[    0.185205] ? __pfx_function_trace_call (kernel/trace/trace_functions.c:210)
[    0.185877] register_ftrace_function_nolock (kernel/trace/ftrace.c:8717)
[    0.186595] register_ftrace_function (kernel/trace/ftrace.c:8745)
[    0.187254] ? __pfx_function_trace_call (kernel/trace/trace_functions.c:210)
[    0.187924] function_trace_init (kernel/trace/trace_functions.c:170)
[    0.188499] tracing_set_tracer (kernel/trace/trace.c:5916 kernel/trace/trace.c:6349)
[    0.189088] register_tracer (kernel/trace/trace.c:2391)
[    0.189642] early_trace_init (kernel/trace/trace.c:11075 kernel/trace/trace.c:11149)
[    0.190204] start_kernel (init/main.c:970)
[    0.190732] x86_64_start_reservations (arch/x86/kernel/head64.c:307)
[    0.191381] x86_64_start_kernel (??:?)
[    0.191955] common_startup_64 (arch/x86/kernel/head_64.S:419)
[    0.192534]  </TASK>
[    0.192839] Modules linked in:
[    0.193267] CR2: 000000000000001c
[    0.193730] ---[ end trace 0000000000000000 ]---

The crash happens because on x86 ftrace allocations from execmem require
maple tree to be initialized.

Move maple tree initialization that depends only on slab availability
earlier in boot so that it will happen right after mm_core_init().

Link: https://lkml.kernel.org/r/20250824130759.1732736-1-rppt@kernel.org
Fixes: 5d79c2be50 ("x86/ftrace: enable EXECMEM_ROX_CACHE for ftrace allocations")
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reported-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Closes: https://lore.kernel.org/all/20250820184743.0302a8b5@gandalf.local.home/
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-03 17:10:36 -07:00
Linus Torvalds
e991acf1bc Merge tag 'mm-nonmm-stable-2025-08-03-12-47' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
 "Significant patch series in this pull request:

   - "squashfs: Remove page->mapping references" (Matthew Wilcox) gets
     us closer to being able to remove page->mapping

   - "relayfs: misc changes" (Jason Xing) does some maintenance and
     minor feature addition work in relayfs

   - "kdump: crashkernel reservation from CMA" (Jiri Bohac) switches
     us from static preallocation of the kdump crashkernel's working
     memory over to dynamic allocation. So the difficulty of a-priori
     estimation of the second kernel's needs is removed and the first
     kernel obtains extra memory

   - "generalize panic_print's dump function to be used by other
     kernel parts" (Feng Tang) implements some consolidation and
     rationalization of the various ways in which a failing kernel
     splats information at the operator

* tag 'mm-nonmm-stable-2025-08-03-12-47' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (80 commits)
  tools/getdelays: add backward compatibility for taskstats version
  kho: add test for kexec handover
  delaytop: enhance error logging and add PSI feature description
  samples: Kconfig: fix spelling mistake "instancess" -> "instances"
  fat: fix too many log in fat_chain_add()
  scripts/spelling.txt: add notifer||notifier to spelling.txt
  xen/xenbus: fix typo "notifer"
  net: mvneta: fix typo "notifer"
  drm/xe: fix typo "notifer"
  cxl: mce: fix typo "notifer"
  KVM: x86: fix typo "notifer"
  MAINTAINERS: add maintainers for delaytop
  ucount: use atomic_long_try_cmpxchg() in atomic_long_inc_below()
  ucount: fix atomic_long_inc_below() argument type
  kexec: enable CMA based contiguous allocation
  stackdepot: make max number of pools boot-time configurable
  lib/xxhash: remove unused functions
  init/Kconfig: restore CONFIG_BROKEN help text
  lib/raid6: update recov_rvv.c zero page usage
  docs: update docs after introducing delaytop
  ...
2025-08-03 16:23:09 -07:00
Lillian Berry
98aa4d5d24 init/main.c: add warning when file specified in rdinit is inaccessible
Avoid silently ignoring the initramfs when the file specified in rdinit is
not usable.  This prints an error that clearly explains the issue (file
was not found, vs initramfs was not found).

Link: https://lkml.kernel.org/r/20250707091411.1412681-1-lillian@star-ark.net
Signed-off-by: Lillian Berry <lillian@star-ark.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-07-19 19:08:26 -07:00
Alexander Shishkin
ce2c403c26 x86/efi: Move runtime service initialization to arch/x86
The EFI call in start_kernel() is guarded by #ifdef CONFIG_X86. Move
the thing to the arch_cpu_finalize_init() path on x86 and get rid of
the #ifdef in start_kernel().

No functional change intended.

Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/all/20250620135325.3300848-5-kirill.shutemov%40linux.intel.com
2025-06-20 10:48:50 -07:00
Huacai Chen
66ac1a4d36 init: fix build warnings about export.h
After commit a934a57a42 ("scripts/misc-check: check missing #include
<linux/export.h> when W=1") and 7d95680d64 ("scripts/misc-check:
check unnecessary #include <linux/export.h> when W=1"), we get some build
warnings with W=1:

init/main.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
init/initramfs.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing

So fix these build warnings for the init code.

Link: https://lkml.kernel.org/r/20250608141235.155206-1-chenhuacai@loongson.cn
Fixes: a934a57a42 ("scripts/misc-check: check missing #include <linux/export.h> when W=1")
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-06-11 22:42:36 -07:00
Linus Torvalds
7d4e49a77d Merge tag 'mm-nonmm-stable-2025-05-31-15-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:

 - "hung_task: extend blocking task stacktrace dump to semaphore" from
   Lance Yang enhances the hung task detector.

   The detector presently dumps the blocking tasks's stack when it is
   blocked on a mutex. Lance's series extends this to semaphores

 - "nilfs2: improve sanity checks in dirty state propagation" from
   Wentao Liang addresses a couple of minor flaws in nilfs2

 - "scripts/gdb: Fixes related to lx_per_cpu()" from Illia Ostapyshyn
   fixes a couple of issues in the gdb scripts

 - "Support kdump with LUKS encryption by reusing LUKS volume keys" from
   Coiby Xu addresses a usability problem with kdump.

   When the dump device is LUKS-encrypted, the kdump kernel may not have
   the keys to the encrypted filesystem. A full writeup of this is in
   the series [0/N] cover letter

 - "sysfs: add counters for lockups and stalls" from Max Kellermann adds
   /sys/kernel/hardlockup_count and /sys/kernel/hardlockup_count and
   /sys/kernel/rcu_stall_count

 - "fork: Page operation cleanups in the fork code" from Pasha Tatashin
   implements a number of code cleanups in fork.c

 - "scripts/gdb/symbols: determine KASLR offset on s390 during early
   boot" from Ilya Leoshkevich fixes some s390 issues in the gdb
   scripts

* tag 'mm-nonmm-stable-2025-05-31-15-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (67 commits)
  llist: make llist_add_batch() a static inline
  delayacct: remove redundant code and adjust indentation
  squashfs: add optional full compressed block caching
  crash_dump, nvme: select CONFIGFS_FS as built-in
  scripts/gdb/symbols: determine KASLR offset on s390 during early boot
  scripts/gdb/symbols: factor out pagination_off()
  scripts/gdb/symbols: factor out get_vmlinux()
  kernel/panic.c: format kernel-doc comments
  mailmap: update and consolidate Casey Connolly's name and email
  nilfs2: remove wbc->for_reclaim handling
  fork: define a local GFP_VMAP_STACK
  fork: check charging success before zeroing stack
  fork: clean-up naming of vm_stack/vm_struct variables in vmap stacks code
  fork: clean-up ifdef logic around stack allocation
  kernel/rcu/tree_stall: add /sys/kernel/rcu_stall_count
  kernel/watchdog: add /sys/kernel/{hard,soft}lockup_count
  x86/crash: make the page that stores the dm crypt keys inaccessible
  x86/crash: pass dm crypt keys to kdump kernel
  Revert "x86/mm: Remove unused __set_memory_prot()"
  crash_dump: retrieve dm crypt keys in kdump kernel
  ...
2025-05-31 19:12:53 -07:00
Linus Torvalds
00c010e130 Merge tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:

 - "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of
   creating a pte which addresses the first page in a folio and reduces
   the amount of plumbing which architecture must implement to provide
   this.

 - "Misc folio patches for 6.16" from Matthew Wilcox is a shower of
   largely unrelated folio infrastructure changes which clean things up
   and better prepare us for future work.

 - "memory,x86,acpi: hotplug memory alignment advisement" from Gregory
   Price adds early-init code to prevent x86 from leaving physical
   memory unused when physical address regions are not aligned to memory
   block size.

 - "mm/compaction: allow more aggressive proactive compaction" from
   Michal Clapinski provides some tuning of the (sadly, hard-coded (more
   sadly, not auto-tuned)) thresholds for our invokation of proactive
   compaction. In a simple test case, the reduction of a guest VM's
   memory consumption was dramatic.

 - "Minor cleanups and improvements to swap freeing code" from Kemeng
   Shi provides some code cleaups and a small efficiency improvement to
   this part of our swap handling code.

 - "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin
   adds the ability for a ptracer to modify syscalls arguments. At this
   time we can alter only "system call information that are used by
   strace system call tampering, namely, syscall number, syscall
   arguments, and syscall return value.

   This series should have been incorporated into mm.git's "non-MM"
   branch, but I goofed.

 - "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from
   Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl
   against /proc/pid/pagemap. This permits CRIU to more efficiently get
   at the info about guard regions.

 - "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan
   implements that fix. No runtime effect is expected because
   validate_page_before_insert() happens to fix up this error.

 - "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David
   Hildenbrand basically brings uprobe text poking into the current
   decade. Remove a bunch of hand-rolled implementation in favor of
   using more current facilities.

 - "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman
   Khandual provides enhancements and generalizations to the pte dumping
   code. This might be needed when 128-bit Page Table Descriptors are
   enabled for ARM.

 - "Always call constructor for kernel page tables" from Kevin Brodsky
   ensures that the ctor/dtor is always called for kernel pgtables, as
   it already is for user pgtables.

   This permits the addition of more functionality such as "insert hooks
   to protect page tables". This change does result in various
   architectures performing unnecesary work, but this is fixed up where
   it is anticipated to occur.

 - "Rust support for mm_struct, vm_area_struct, and mmap" from Alice
   Ryhl adds plumbing to permit Rust access to core MM structures.

 - "fix incorrectly disallowed anonymous VMA merges" from Lorenzo
   Stoakes takes advantage of some VMA merging opportunities which we've
   been missing for 15 years.

 - "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from
   SeongJae Park optimizes process_madvise()'s TLB flushing.

   Instead of flushing each address range in the provided iovec, we
   batch the flushing across all the iovec entries. The syscall's cost
   was approximately halved with a microbenchmark which was designed to
   load this particular operation.

 - "Track node vacancy to reduce worst case allocation counts" from
   Sidhartha Kumar makes the maple tree smarter about its node
   preallocation.

   stress-ng mmap performance increased by single-digit percentages and
   the amount of unnecessarily preallocated memory was dramaticelly
   reduced.

 - "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes
   a few unnecessary things which Baoquan noted when reading the code.

 - ""Enhance sysfs handling for memory hotplug in weighted interleave"
   from Rakie Kim "enhances the weighted interleave policy in the memory
   management subsystem by improving sysfs handling, fixing memory
   leaks, and introducing dynamic sysfs updates for memory hotplug
   support". Fixes things on error paths which we are unlikely to hit.

 - "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory"
   from SeongJae Park introduces new DAMOS quota goal metrics which
   eliminate the manual tuning which is required when utilizing DAMON
   for memory tiering.

 - "mm/vmalloc.c: code cleanup and improvements" from Baoquan He
   provides cleanups and small efficiency improvements which Baoquan
   found via code inspection.

 - "vmscan: enforce mems_effective during demotion" from Gregory Price
   changes reclaim to respect cpuset.mems_effective during demotion when
   possible. because presently, reclaim explicitly ignores
   cpuset.mems_effective when demoting, which may cause the cpuset
   settings to violated.

   This is useful for isolating workloads on a multi-tenant system from
   certain classes of memory more consistently.

 - "Clean up split_huge_pmd_locked() and remove unnecessary folio
   pointers" from Gavin Guo provides minor cleanups and efficiency gains
   in in the huge page splitting and migrating code.

 - "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache
   for `struct mem_cgroup', yielding improved memory utilization.

 - "add max arg to swappiness in memory.reclaim and lru_gen" from
   Zhongkun He adds a new "max" argument to the "swappiness=" argument
   for memory.reclaim MGLRU's lru_gen.

   This directs proactive reclaim to reclaim from only anon folios
   rather than file-backed folios.

 - "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the
   first step on the path to permitting the kernel to maintain existing
   VMs while replacing the host kernel via file-based kexec. At this
   time only memblock's reserve_mem is preserved.

 - "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides
   and uses a smarter way of looping over a pfn range. By skipping
   ranges of invalid pfns.

 - "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via
   cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning
   when a task is pinned a single NUMA mode.

   Dramatic performance benefits were seen in some real world cases.

 - "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank
   Garg addresses a warning which occurs during memory compaction when
   using JFS.

 - "move all VMA allocation, freeing and duplication logic to mm" from
   Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more
   appropriate mm/vma.c.

 - "mm, swap: clean up swap cache mapping helper" from Kairui Song
   provides code consolidation and cleanups related to the folio_index()
   function.

 - "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that.

 - "memcg: Fix test_memcg_min/low test failures" from Waiman Long
   addresses some bogus failures which are being reported by the
   test_memcontrol selftest.

 - "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo
   Stoakes commences the deprecation of file_operations.mmap() in favor
   of the new file_operations.mmap_prepare().

   The latter is more restrictive and prevents drivers from messing with
   things in ways which, amongst other problems, may defeat VMA merging.

 - "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples
   the per-cpu memcg charge cache from the objcg's one.

   This is a step along the way to making memcg and objcg charging
   NMI-safe, which is a BPF requirement.

 - "mm/damon: minor fixups and improvements for code, tests, and
   documents" from SeongJae Park is yet another batch of miscellaneous
   DAMON changes. Fix and improve minor problems in code, tests and
   documents.

 - "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg
   stats to be irq safe. Another step along the way to making memcg
   charging and stats updates NMI-safe, a BPF requirement.

 - "Let unmap_hugepage_range() and several related functions take folio
   instead of page" from Fan Ni provides folio conversions in the
   hugetlb code.

* tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits)
  mm: pcp: increase pcp->free_count threshold to trigger free_high
  mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range()
  mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: pass folio instead of page to unmap_ref_private()
  memcg: objcg stock trylock without irq disabling
  memcg: no stock lock for cpu hot-unplug
  memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs
  memcg: make count_memcg_events re-entrant safe against irqs
  memcg: make mod_memcg_state re-entrant safe against irqs
  memcg: move preempt disable to callers of memcg_rstat_updated
  memcg: memcg_rstat_updated re-entrant safe against irqs
  mm: khugepaged: decouple SHMEM and file folios' collapse
  selftests/eventfd: correct test name and improve messages
  alloc_tag: check mem_profiling_support in alloc_tag_init
  Docs/damon: update titles and brief introductions to explain DAMOS
  selftests/damon/_damon_sysfs: read tried regions directories in order
  mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject()
  mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat()
  mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs
  ...
2025-05-31 15:44:16 -07:00
Huan Yang
bc9817bb7a mm/memcg: move mem_cgroup_init() ahead of cgroup_init()
Patch series "Use kmem_cache for memcg alloc", v3.

(willy tldr: "you've gone from allocating 8 objects per 32KiB to
allocating 13 objects per 32KiB, a 62% improvement in memory consumption"
[1])


The mem_cgroup_alloc function creates mem_cgroup struct and it's
associated structures including mem_cgroup_per_node.  Through detailed
analysis on our test machine (Arm64, 16GB RAM, 6.6 kernel, 1 NUMA node,
memcgv2 with nokmem,nosocket,cgroup_disable=pressure), we can observe the
memory allocation for these structures using the following shell commands:

  # Enable tracing
  echo 1 > /sys/kernel/tracing/events/kmem/kmalloc/enable
  echo 1 > /sys/kernel/tracing/tracing_on
  cat /sys/kernel/tracing/trace_pipe | grep kmalloc | grep mem_cgroup

  # Trigger allocation if cgroup subtree do not enable memcg
  echo +memory > /sys/fs/cgroup/cgroup.subtree_control

Ftrace Output:

  # mem_cgroup struct allocation
  sh-6312    [000] ..... 58015.698365: kmalloc:
    call_site=mem_cgroup_css_alloc+0xd8/0x5b4
    ptr=000000003e4c3799 bytes_req=2312 bytes_alloc=4096
    gfp_flags=GFP_KERNEL|__GFP_ZERO node=-1 accounted=false

  # mem_cgroup_per_node allocation
  sh-6312    [000] ..... 58015.698389: kmalloc:
    call_site=mem_cgroup_css_alloc+0x1d8/0x5b4
    ptr=00000000d798700c bytes_req=2896 bytes_alloc=4096
    gfp_flags=GFP_KERNEL|__GFP_ZERO node=0 accounted=false

Key Observations:

  1. Both structures use kmalloc with requested sizes between 2KB-4KB
  2. Allocation alignment forces 4KB slab usage due to pre-defined sizes
     (64B, 128B,..., 2KB, 4KB, 8KB)
  3. Memory waste per memcg instance:
      Base struct: 4096 - 2312 = 1784 bytes
      Per-node struct: 4096 - 2896 = 1200 bytes
      Total waste: 2984 bytes (1-node system)
      NUMA scaling: (1200 + 8) * nr_node_ids bytes

So, it's a little waste.

This patchset introduces dedicated kmem_cache:
  Patch2 - mem_cgroup kmem_cache - memcg_cachep
  Patch3 - mem_cgroup_per_node kmem_cache - memcg_pn_cachep

The benefits of this change can be observed with the following tracing
commands:

  # Enable tracing
  echo 1 > /sys/kernel/tracing/events/kmem/kmem_cache_alloc/enable
  echo 1 > /sys/kernel/tracing/tracing_on
  cat /sys/kernel/tracing/trace_pipe | grep kmem_cache_alloc | grep mem_cgroup
  # In another terminal:
  echo +memory > /sys/fs/cgroup/cgroup.subtree_control


The output might now look like this:

  # mem_cgroup struct allocation
  sh-9827     [000] .....   289.513598: kmem_cache_alloc:
    call_site=mem_cgroup_css_alloc+0xbc/0x5d4 ptr=00000000695c1806
    bytes_req=2312 bytes_alloc=2368 gfp_flags=GFP_KERNEL|__GFP_ZERO node=-1
    accounted=false
  # mem_cgroup_per_node allocation
  sh-9827     [000] .....   289.513602: kmem_cache_alloc:
    call_site=mem_cgroup_css_alloc+0x1b8/0x5d4 ptr=000000002989e63a
    bytes_req=2896 bytes_alloc=2944 gfp_flags=GFP_KERNEL|__GFP_ZERO node=0
    accounted=false

This indicates that the `mem_cgroup` struct now requests 2312 bytes and is
allocated 2368 bytes, while `mem_cgroup_per_node` requests 2896 bytes and
is allocated 2944 bytes.  The slight increase in allocated size is due to
`SLAB_HWCACHE_ALIGN` in the `kmem_cache`.

Without `SLAB_HWCACHE_ALIGN`, the allocation might appear as:

  # mem_cgroup struct allocation
  sh-9269     [003] .....    80.396366: kmem_cache_alloc:
    call_site=mem_cgroup_css_alloc+0xbc/0x5d4 ptr=000000005b12b475
    bytes_req=2312 bytes_alloc=2312 gfp_flags=GFP_KERNEL|__GFP_ZERO node=-1
    accounted=false

  # mem_cgroup_per_node allocation
  sh-9269     [003] .....    80.396411: kmem_cache_alloc:
    call_site=mem_cgroup_css_alloc+0x1b8/0x5d4 ptr=00000000f347adc6
    bytes_req=2896 bytes_alloc=2896 gfp_flags=GFP_KERNEL|__GFP_ZERO node=0
    accounted=false

While the `bytes_alloc` now matches the `bytes_req`, this patchset
defaults to using `SLAB_HWCACHE_ALIGN` as it is generally considered more
beneficial for performance.  Please let me know if there are any issues or
if I've misunderstood anything.

This patchset also move mem_cgroup_init ahead of cgroup_init() due to
cgroup_init() will allocate root_mem_cgroup, but each initcall invoke
after cgroup_init, so if each kmem_cache do not prepare, we need testing
NULL before use it.


This patch (of 3):

When cgroup_init() creates root_mem_cgroup through css_alloc callback,
some critical resources might not be fully initialized, forcing later
operations to perform conditional checks for resource availability.

This patch move mem_cgroup_init() to address the init order, it invoke
before cgroup_init, so, compare to subsys_initcall, it can use to prepare
some key resources before root_mem_cgroup alloc.

Link: https://lkml.kernel.org/r/aAsRCj-niMMTtmK8@casper.infradead.org [1]
Link: https://lkml.kernel.org/r/20250425031935.76411-1-link@vivo.com
Link: https://lkml.kernel.org/r/20250425031935.76411-2-link@vivo.com
Signed-off-by: Huan Yang <link@vivo.com>
Suggested-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Francesco Valla <francesco@valla.it>
Cc: guoweikang <guoweikang.kernel@gmail.com>
Cc: Huang Shijie <shijie@os.amperecomputing.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Raul E Rangel <rrangel@chromium.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-12 23:50:34 -07:00
Francesco Valla
3330dc1b20 init/main.c: log initcall level when initcall_debug is used
When initcall_debug is specified on the command line, the start and return
point for each initcall is printed.  However, no information on the
initcall level is reported.

Add to the initcall_debug infrastructure an additional print that informs
when a new initcall level is entered.  This is particularly useful when
debugging dependency chains and/or working on boot time reduction.

Link: https://lkml.kernel.org/r/20250316205014.2830071-2-francesco@valla.it
Signed-off-by: Francesco Valla <francesco@valla.it>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tim Bird <tim.bird@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-11 17:54:04 -07:00
Ingo Molnar
751e6a394c timers: Rename init_timers() as timers_init()
Move this API to the canonical timers_*() namespace.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250507175338.672442-8-mingo@kernel.org
2025-05-08 19:49:33 +02:00
Paul E. McKenney
23c22d9156 rcu-tasks: Move RCU Tasks self-tests to core_initcall()
The timer and hrtimer softirq processing has moved to dedicated threads
for kernels built with CONFIG_IRQ_FORCED_THREADING=y.  This results in
timers not expiring until later in early boot, which in turn causes the
RCU Tasks self-tests to hang in kernels built with CONFIG_PROVE_RCU=y,
which further causes the entire kernel to hang.  One fix would be to
make timers work during this time, but there are no known users of RCU
Tasks grace periods during that time, so no justification for the added
complexity.  Not yet, anyway.

This commit therefore moves the call to rcu_init_tasks_generic() from
kernel_init_freeable() to a core_initcall().  This works because the
timer and hrtimer kthreads are created at early_initcall() time.

Fixes: 49a1763950 ("softirq: Use a dedicated thread for timer wakeups on PREEMPT_RT.")
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: <linux-trace-kernel@vger.kernel.org>
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2025-03-04 18:44:28 -08:00
Linus Torvalds
9c5968db9e Merge tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
 "The various patchsets are summarized below. Plus of course many
  indivudual patches which are described in their changelogs.

   - "Allocate and free frozen pages" from Matthew Wilcox reorganizes
     the page allocator so we end up with the ability to allocate and
     free zero-refcount pages. So that callers (ie, slab) can avoid a
     refcount inc & dec

   - "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to
     use large folios other than PMD-sized ones

   - "Fix mm/rodata_test" from Petr Tesarik performs some maintenance
     and fixes for this small built-in kernel selftest

   - "mas_anode_descend() related cleanup" from Wei Yang tidies up part
     of the mapletree code

   - "mm: fix format issues and param types" from Keren Sun implements a
     few minor code cleanups

   - "simplify split calculation" from Wei Yang provides a few fixes and
     a test for the mapletree code

   - "mm/vma: make more mmap logic userland testable" from Lorenzo
     Stoakes continues the work of moving vma-related code into the
     (relatively) new mm/vma.c

   - "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David
     Hildenbrand cleans up and rationalizes handling of gfp flags in the
     page allocator

   - "readahead: Reintroduce fix for improper RA window sizing" from Jan
     Kara is a second attempt at fixing a readahead window sizing issue.
     It should reduce the amount of unnecessary reading

   - "synchronously scan and reclaim empty user PTE pages" from Qi Zheng
     addresses an issue where "huge" amounts of pte pagetables are
     accumulated:

       https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/

     Qi's series addresses this windup by synchronously freeing PTE
     memory within the context of madvise(MADV_DONTNEED)

   - "selftest/mm: Remove warnings found by adding compiler flags" from
     Muhammad Usama Anjum fixes some build warnings in the selftests
     code when optional compiler warnings are enabled

   - "mm: don't use __GFP_HARDWALL when migrating remote pages" from
     David Hildenbrand tightens the allocator's observance of
     __GFP_HARDWALL

   - "pkeys kselftests improvements" from Kevin Brodsky implements
     various fixes and cleanups in the MM selftests code, mainly
     pertaining to the pkeys tests

   - "mm/damon: add sample modules" from SeongJae Park enhances DAMON to
     estimate application working set size

   - "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn
     provides some cleanups to memcg's hugetlb charging logic

   - "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song
     removes the global swap cgroup lock. A speedup of 10% for a
     tmpfs-based kernel build was demonstrated

   - "zram: split page type read/write handling" from Sergey Senozhatsky
     has several fixes and cleaups for zram in the area of
     zram_write_page(). A watchdog softlockup warning was eliminated

   - "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin
     Brodsky cleans up the pagetable destructor implementations. A rare
     use-after-free race is fixed

   - "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes
     simplifies and cleans up the debugging code in the VMA merging
     logic

   - "Account page tables at all levels" from Kevin Brodsky cleans up
     and regularizes the pagetable ctor/dtor handling. This results in
     improvements in accounting accuracy

   - "mm/damon: replace most damon_callback usages in sysfs with new
     core functions" from SeongJae Park cleans up and generalizes
     DAMON's sysfs file interface logic

   - "mm/damon: enable page level properties based monitoring" from
     SeongJae Park increases the amount of information which is
     presented in response to DAMOS actions

   - "mm/damon: remove DAMON debugfs interface" from SeongJae Park
     removes DAMON's long-deprecated debugfs interfaces. Thus the
     migration to sysfs is completed

   - "mm/hugetlb: Refactor hugetlb allocation resv accounting" from
     Peter Xu cleans up and generalizes the hugetlb reservation
     accounting

   - "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino
     removes a never-used feature of the alloc_pages_bulk() interface

   - "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park
     extends DAMOS filters to support not only exclusion (rejecting),
     but also inclusion (allowing) behavior

   - "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi
     introduces a new memory descriptor for zswap.zpool that currently
     overlaps with struct page for now. This is part of the effort to
     reduce the size of struct page and to enable dynamic allocation of
     memory descriptors

   - "mm, swap: rework of swap allocator locks" from Kairui Song redoes
     and simplifies the swap allocator locking. A speedup of 400% was
     demonstrated for one workload. As was a 35% reduction for kernel
     build time with swap-on-zram

   - "mm: update mips to use do_mmap(), make mmap_region() internal"
     from Lorenzo Stoakes reworks MIPS's use of mmap_region() so that
     mmap_region() can be made MM-internal

   - "mm/mglru: performance optimizations" from Yu Zhao fixes a few
     MGLRU regressions and otherwise improves MGLRU performance

   - "Docs/mm/damon: add tuning guide and misc updates" from SeongJae
     Park updates DAMON documentation

   - "Cleanup for memfd_create()" from Isaac Manjarres does that thing

   - "mm: hugetlb+THP folio and migration cleanups" from David
     Hildenbrand provides various cleanups in the areas of hugetlb
     folios, THP folios and migration

   - "Uncached buffered IO" from Jens Axboe implements the new
     RWF_DONTCACHE flag which provides synchronous dropbehind for
     pagecache reading and writing. To permite userspace to address
     issues with massive buildup of useless pagecache when
     reading/writing fast devices

   - "selftests/mm: virtual_address_range: Reduce memory" from Thomas
     Weißschuh fixes and optimizes some of the MM selftests"

* tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
  mm/compaction: fix UBSAN shift-out-of-bounds warning
  s390/mm: add missing ctor/dtor on page table upgrade
  kasan: sw_tags: use str_on_off() helper in kasan_init_sw_tags()
  tools: add VM_WARN_ON_VMG definition
  mm/damon/core: use str_high_low() helper in damos_wmark_wait_us()
  seqlock: add missing parameter documentation for raw_seqcount_try_begin()
  mm/page-writeback: consolidate wb_thresh bumping logic into __wb_calc_thresh
  mm/page_alloc: remove the incorrect and misleading comment
  zram: remove zcomp_stream_put() from write_incompressible_page()
  mm: separate move/undo parts from migrate_pages_batch()
  mm/kfence: use str_write_read() helper in get_access_type()
  selftests/mm/mkdirty: fix memory leak in test_uffdio_copy()
  kasan: hw_tags: Use str_on_off() helper in kasan_init_hw_tags()
  selftests/mm: virtual_address_range: avoid reading from VM_IO mappings
  selftests/mm: vm_util: split up /proc/self/smaps parsing
  selftests/mm: virtual_address_range: unmap chunks after validation
  selftests/mm: virtual_address_range: mmap() without PROT_WRITE
  selftests/memfd/memfd_test: fix possible NULL pointer dereference
  mm: add FGP_DONTCACHE folio creation flag
  mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue
  ...
2025-01-26 18:36:23 -08:00
Guo Weikang
c6f239796b mm/memblock: add memblock_alloc_or_panic interface
Before SLUB initialization, various subsystems used memblock_alloc to
allocate memory.  In most cases, when memory allocation fails, an
immediate panic is required.  To simplify this behavior and reduce
repetitive checks, introduce `memblock_alloc_or_panic`.  This function
ensures that memory allocation failures result in a panic automatically,
improving code readability and consistency across subsystems that require
this behavior.

[guoweikang.kernel@gmail.com: arch/s390: save_area_alloc default failure behavior changed to panic]
  Link: https://lkml.kernel.org/r/20250109033136.2845676-1-guoweikang.kernel@gmail.com
  Link: https://lore.kernel.org/lkml/Z2fknmnNtiZbCc7x@kernel.org/
Link: https://lkml.kernel.org/r/20250102072528.650926-1-guoweikang.kernel@gmail.com
Signed-off-by: Guo Weikang <guoweikang.kernel@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>	[m68k]
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>	[s390]
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-25 20:22:38 -08:00
Uladzislau Rezki (Sony)
0f52b4db4f rcu/kvfree: Initialize kvfree_rcu() separately
Introduce a separate initialization of kvfree_rcu() functionality.
For such purpose a kfree_rcu_batch_init() is renamed to a kvfree_rcu_init()
and it is invoked from the main.c right after rcu_init() is done.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: Hyeonggon Yoo <hyeonggon.yoo@sk.com>
Tested-by: Hyeonggon Yoo <hyeonggon.yoo@sk.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2025-01-11 20:39:02 +01:00
Raul E Rangel
17b655759e init: Don't proxy console= to earlycon
Today we are proxying the `console=` command line args to the
`param_setup_earlycon()` handler. This is done because the following are
equivalent:

    console=uart[8250],mmio,<addr>[,options]
    earlycon=uart[8250],mmio,<addr>[,options]

Both invocations enable an early `bootconsole`. `console=uartXXXX` is
just an alias for `earlycon=uartXXXX`.

In addition, when `earlycon=` (empty value) or just `earlycon`
(no value) is specified on the command line, we enable the earlycon
`bootconsole` specified by the SPCR table or the DT.

The problem arises when `console=` (empty value) is specified on the
command line. It's intention is to disable the `console`, but what
happens instead is that the SPRC/DT console gets enabled.

This happens because we are proxying the `console=` (empty value)
parameter to the `earlycon` handler. The `earlycon` handler then sees
that the parameter value is empty, so it enables the SPCR/DT
`bootconsole`.

This change makes it so that the `console` or `console=` parameters no
longer enable the SPCR/DT `bootconsole`. I also cleans up the hack in
`main.c` that would forward the `console` parameter to the `earlycon`
handler.

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240911123507.v2.1.Id08823b2f848237ae90ce5c5fa7e027e97c33ad3@changeid
Signed-off-by: Petr Mladek <pmladek@suse.com>
2024-10-01 14:11:39 +02:00
KP Singh
77b644c39d init/main.c: Initialize early LSMs after arch code, static keys and calls.
With LSMs using static calls and static keys, early_lsm_init needs to
wait for setup_arch for architecture specific functionality which
includes jump tables and static calls to be initialized.

Since not all architectures call jump_table_init in setup_arch,
explicitly call both jump_table_init and static_call_init before
early_security_init.

This only affects "early LSMs" i.e. only lockdown when
CONFIG_SECURITY_LOCKDOWN_LSM_EARLY is set.

Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-20 14:05:33 -04:00
Linus Torvalds
eb6a9339ef Merge tag 'mm-nonmm-stable-2024-05-19-11-56' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-mm updates from Andrew Morton:
 "Mainly singleton patches, documented in their respective changelogs.
  Notable series include:

   - Some maintenance and performance work for ocfs2 in Heming Zhao's
     series "improve write IO performance when fragmentation is high".

   - Some ocfs2 bugfixes from Su Yue in the series "ocfs2 bugs fixes
     exposed by fstests".

   - kfifo header rework from Andy Shevchenko in the series "kfifo:
     Clean up kfifo.h".

   - GDB script fixes from Florian Rommel in the series "scripts/gdb:
     Fixes for $lx_current and $lx_per_cpu".

   - After much discussion, a coding-style update from Barry Song
     explaining one reason why inline functions are preferred over
     macros. The series is "codingstyle: avoid unused parameters for a
     function-like macro""

* tag 'mm-nonmm-stable-2024-05-19-11-56' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (62 commits)
  fs/proc: fix softlockup in __read_vmcore
  nilfs2: convert BUG_ON() in nilfs_finish_roll_forward() to WARN_ON()
  scripts: checkpatch: check unused parameters for function-like macro
  Documentation: coding-style: ask function-like macros to evaluate parameters
  nilfs2: use __field_struct() for a bitwise field
  selftests/kcmp: remove unused open mode
  nilfs2: remove calls to folio_set_error() and folio_clear_error()
  kernel/watchdog_perf.c: tidy up kerneldoc
  watchdog: allow nmi watchdog to use raw perf event
  watchdog: handle comma separated nmi_watchdog command line
  nilfs2: make superblock data array index computation sparse friendly
  squashfs: remove calls to set the folio error flag
  squashfs: convert squashfs_symlink_read_folio to use folio APIs
  scripts/gdb: fix detection of current CPU in KGDB
  scripts/gdb: make get_thread_info accept pointers
  scripts/gdb: fix parameter handling in $lx_per_cpu
  scripts/gdb: fix failing KGDB detection during probe
  kfifo: don't use "proxy" headers
  media: stih-cec: add missing io.h
  media: rc: add missing io.h
  ...
2024-05-19 14:02:03 -07:00
Linus Torvalds
e9d6825180 Merge tag 'bootconfig-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull bootconfig updates from Masami Hiramatsu:

 - Do not put unneeded quotes on the extra command line items which was
   inserted from the bootconfig.

 - Remove redundant spaces from the extra command line.

* tag 'bootconfig-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  init/main.c: Minor cleanup for the setup_command_line() function
  init/main.c: Remove redundant space from saved_command_line
  bootconfig: do not put quotes on cmdline items unless necessary
2024-05-17 18:23:55 -07:00
Linus Torvalds
48fc82c40b Merge tag 'locking-core-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:

 - Over a dozen code generation micro-optimizations for the atomic
   and spinlock code

 - Add more __ro_after_init attributes

 - Robustify the lockdevent_*() macros

* tag 'locking-core-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/pvqspinlock/x86: Use _Q_LOCKED_VAL in PV_UNLOCK_ASM macro
  locking/qspinlock/x86: Micro-optimize virt_spin_lock()
  locking/atomic/x86: Merge __arch{,_try}_cmpxchg64_emu_local() with __arch{,_try}_cmpxchg64_emu()
  locking/atomic/x86: Introduce arch_try_cmpxchg64_local()
  locking/pvqspinlock/x86: Remove redundant CMP after CMPXCHG in __raw_callee_save___pv_queued_spin_unlock()
  locking/pvqspinlock: Use try_cmpxchg() in qspinlock_paravirt.h
  locking/pvqspinlock: Use try_cmpxchg_acquire() in trylock_clear_pending()
  locking/qspinlock: Use atomic_try_cmpxchg_relaxed() in xchg_tail()
  locking/atomic/x86: Define arch_atomic_sub() family using arch_atomic_add() functions
  locking/atomic/x86: Rewrite x86_32 arch_atomic64_{,fetch}_{and,or,xor}() functions
  locking/atomic/x86: Introduce arch_atomic64_read_nonatomic() to x86_32
  locking/atomic/x86: Introduce arch_atomic64_try_cmpxchg() to x86_32
  locking/atomic/x86: Introduce arch_try_cmpxchg64() for !CONFIG_X86_CMPXCHG64
  locking/atomic/x86: Modernize x86_32 arch_{,try_}_cmpxchg64{,_local}()
  locking/atomic/x86: Correct the definition of __arch_try_cmpxchg128()
  x86/tsc: Make __use_tsc __ro_after_init
  x86/kvm: Make kvm_async_pf_enabled __ro_after_init
  context_tracking: Make context_tracking_key __ro_after_init
  jump_label,module: Don't alloc static_key_mod for __ro_after_init keys
  locking/qspinlock: Always evaluate lockevent* non-event parameter once
2024-05-13 17:01:28 -07:00
Huang Shijie
f9899c0281 NUMA: early use of cpu_to_node() returns 0 instead of the correct node id
During the kernel booting, the generic cpu_to_node() is called too early
in arm64, powerpc and riscv when CONFIG_NUMA is enabled.

There are at least four places in the common code where
the generic cpu_to_node() is called before it is initialized:
	   1.) early_trace_init()         in kernel/trace/trace.c
	   2.) sched_init()               in kernel/sched/core.c
	   3.) init_sched_fair_class()    in kernel/sched/fair.c
	   4.) workqueue_init_early()     in kernel/workqueue.c

This will harm performance since there is an increase in off node
accesses.

In order to fix the bug, the patch introduces early_numa_node_init() which
is called after smp_prepare_boot_cpu() in start_kernel. 
early_numa_node_init will initialize the "numa_node" as soon as the
early_cpu_to_node() is ready, before the cpu_to_node() is called at the
first time.

Link: https://lkml.kernel.org/r/20240126064451.5465-1-shijie@os.amperecomputing.com
Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>	[RISC-V]
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michael Kelley (LINUX) <mikelley@microsoft.com>
Cc: "Mike Rapoport (IBM)" <rppt@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25 21:07:03 -07:00
Rasmus Villemoes
212f863fa8 bootconfig: do not put quotes on cmdline items unless necessary
When trying to migrate to using bootconfig to embed the kernel's and
PID1's command line with the kernel image itself, and so allowing changing
that without modifying the bootloader, I noticed that /proc/cmdline
changed from e.g.

  console=ttymxc0,115200n8 cma=128M quiet -- --log-level=notice

to

  console="ttymxc0,115200n8" cma="128M" quiet -- --log-level="notice"

The kernel parameters are parsed just fine, and the quotes are indeed
stripped from the actual argv[] given to PID1.  However, the quoting
doesn't really serve any purpose and looks excessive, and might confuse
some (naive) userspace tool trying to parse /proc/cmdline.  So do not
quote the value unless it contains whitespace.

Link: https://lkml.kernel.org/r/20240320101952.62135-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-04-25 21:07:01 -07:00
Yuntao Wang
ddd53363f8 init/main.c: Minor cleanup for the setup_command_line() function
This is just a minor cleanup to make the code look a bit cleaner.

Link: https://lore.kernel.org/all/20240412081733.35925-3-ytcoode@gmail.com/

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-04-13 01:03:13 +09:00
Yuntao Wang
cd24bdb068 init/main.c: Remove redundant space from saved_command_line
There is a space at the end of extra_init_args. In the current logic,
copying extra_init_args to saved_command_line will cause extra spaces
in saved_command_line here or there. Remove the trailing space from
extra_init_args to make the string in saved_command_line look more perfect.

Link: https://lore.kernel.org/all/20240412032950.12687-1-ytcoode@gmail.com/

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-04-13 01:02:08 +09:00
Rasmus Villemoes
efee03a50c bootconfig: do not put quotes on cmdline items unless necessary
When trying to migrate to using bootconfig to embed the kernel's and
PID1's command line with the kernel image itself, and so allowing
changing that without modifying the bootloader, I noticed that
/proc/cmdline changed from e.g.

  console=ttymxc0,115200n8 cma=128M quiet -- --log-level=notice

to

  console="ttymxc0,115200n8" cma="128M" quiet -- --log-level="notice"

The kernel parameters are parsed just fine, and the quotes are indeed
stripped from the actual argv[] given to PID1. However, the quoting
doesn't really serve any purpose and looks excessive, and might
confuse some (naive) userspace tool trying to parse /proc/cmdline. So
do not quote the value unless it contains whitespace.

Link: https://lore.kernel.org/all/20240308124401.1702046-1-linux@rasmusvillemoes.dk/

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-04-13 01:02:08 +09:00
Yuntao Wang
46dad3c1e5 init/main.c: Fix potential static_command_line memory overflow
We allocate memory of size 'xlen + strlen(boot_command_line) + 1' for
static_command_line, but the strings copied into static_command_line are
extra_command_line and command_line, rather than extra_command_line and
boot_command_line.

When strlen(command_line) > strlen(boot_command_line), static_command_line
will overflow.

This patch just recovers strlen(command_line) which was miss-consolidated
with strlen(boot_command_line) in the commit f5c7310ac7 ("init/main: add
checks for the return value of memblock_alloc*()")

Link: https://lore.kernel.org/all/20240412081733.35925-2-ytcoode@gmail.com/

Fixes: f5c7310ac7 ("init/main: add checks for the return value of memblock_alloc*()")
Cc: stable@vger.kernel.org
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-04-13 00:59:36 +09:00
Masami Hiramatsu
c722cea208 fs/proc: Skip bootloader comment if no embedded kernel parameters
If the "bootconfig" kernel command-line argument was specified or if
the kernel was built with CONFIG_BOOT_CONFIG_FORCE, but if there are
no embedded kernel parameter, omit the "# Parameters from bootloader:"
comment from the /proc/bootconfig file.  This will cause automation
to fall back to the /proc/cmdline file, which will be identical to the
comment in this no-embedded-kernel-parameters case.

Link: https://lore.kernel.org/all/20240409044358.1156477-2-paulmck@kernel.org/

Fixes: 8b8ce6c75430 ("fs/proc: remove redundant comments from /proc/bootconfig")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: stable@vger.kernel.org
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-04-09 23:36:18 +09:00
Peter Zijlstra
91a1d97ef4 jump_label,module: Don't alloc static_key_mod for __ro_after_init keys
When a static_key is marked ro_after_init, its state will never change
(after init), therefore jump_label_update() will never need to iterate
the entries, and thus module load won't actually need to track this --
avoiding the static_key::next write.

Therefore, mark these keys such that jump_label_add_module() might
recognise them and avoid the modification.

Use the special state: 'static_key_linked(key) && !static_key_mod(key)'
to denote such keys.

jump_label_add_module() does not exist under CONFIG_JUMP_LABEL=n, so the
newly-introduced jump_label_init_ro() can be defined as a nop for that
configuration.

[ mingo: Renamed jump_label_ro() to jump_label_init_ro() ]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20240313180106.2917308-2-vschneid@redhat.com
2024-03-22 11:18:16 +01:00
Linus Torvalds
e5eb28f6d1 Merge tag 'mm-nonmm-stable-2024-03-14-09-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:

 - Kuan-Wei Chiu has developed the well-named series "lib min_heap: Min
   heap optimizations".

 - Kuan-Wei Chiu has also sped up the library sorting code in the series
   "lib/sort: Optimize the number of swaps and comparisons".

 - Alexey Gladkov has added the ability for code running within an IPC
   namespace to alter its IPC and MQ limits. The series is "Allow to
   change ipc/mq sysctls inside ipc namespace".

 - Geert Uytterhoeven has contributed some dhrystone maintenance work in
   the series "lib: dhry: miscellaneous cleanups".

 - Ryusuke Konishi continues nilfs2 maintenance work in the series

	"nilfs2: eliminate kmap and kmap_atomic calls"
	"nilfs2: fix kernel bug at submit_bh_wbc()"

 - Nathan Chancellor has updated our build tools requirements in the
   series "Bump the minimum supported version of LLVM to 13.0.1".

 - Muhammad Usama Anjum continues with the selftests maintenance work in
   the series "selftests/mm: Improve run_vmtests.sh".

 - Oleg Nesterov has done some maintenance work against the signal code
   in the series "get_signal: minor cleanups and fix".

Plus the usual shower of singleton patches in various parts of the tree.
Please see the individual changelogs for details.

* tag 'mm-nonmm-stable-2024-03-14-09-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (77 commits)
  nilfs2: prevent kernel bug at submit_bh_wbc()
  nilfs2: fix failure to detect DAT corruption in btree and direct mappings
  ocfs2: enable ocfs2_listxattr for special files
  ocfs2: remove SLAB_MEM_SPREAD flag usage
  assoc_array: fix the return value in assoc_array_insert_mid_shortcut()
  buildid: use kmap_local_page()
  watchdog/core: remove sysctl handlers from public header
  nilfs2: use div64_ul() instead of do_div()
  mul_u64_u64_div_u64: increase precision by conditionally swapping a and b
  kexec: copy only happens before uchunk goes to zero
  get_signal: don't initialize ksig->info if SIGNAL_GROUP_EXIT/group_exec_task
  get_signal: hide_si_addr_tag_bits: fix the usage of uninitialized ksig
  get_signal: don't abuse ksig->info.si_signo and ksig->sig
  const_structs.checkpatch: add device_type
  Normalise "name (ad@dr)" MODULE_AUTHORs to "name <ad@dr>"
  dyndbg: replace kstrdup() + strchr() with kstrdup_and_replace()
  list: leverage list_is_head() for list_entry_is_head()
  nilfs2: MAINTAINERS: drop unreachable project mirror site
  smp: make __smp_processor_id() 0-argument macro
  fat: fix uninitialized field in nostale filehandles
  ...
2024-03-14 18:03:09 -07:00
Linus Torvalds
902861e34c Merge tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:

 - Sumanth Korikkar has taught s390 to allocate hotplug-time page frames
   from hotplugged memory rather than only from main memory. Series
   "implement "memmap on memory" feature on s390".

 - More folio conversions from Matthew Wilcox in the series

	"Convert memcontrol charge moving to use folios"
	"mm: convert mm counter to take a folio"

 - Chengming Zhou has optimized zswap's rbtree locking, providing
   significant reductions in system time and modest but measurable
   reductions in overall runtimes. The series is "mm/zswap: optimize the
   scalability of zswap rb-tree".

 - Chengming Zhou has also provided the series "mm/zswap: optimize zswap
   lru list" which provides measurable runtime benefits in some
   swap-intensive situations.

 - And Chengming Zhou further optimizes zswap in the series "mm/zswap:
   optimize for dynamic zswap_pools". Measured improvements are modest.

 - zswap cleanups and simplifications from Yosry Ahmed in the series
   "mm: zswap: simplify zswap_swapoff()".

 - In the series "Add DAX ABI for memmap_on_memory", Vishal Verma has
   contributed several DAX cleanups as well as adding a sysfs tunable to
   control the memmap_on_memory setting when the dax device is
   hotplugged as system memory.

 - Johannes Weiner has added the large series "mm: zswap: cleanups",
   which does that.

 - More DAMON work from SeongJae Park in the series

	"mm/damon: make DAMON debugfs interface deprecation unignorable"
	"selftests/damon: add more tests for core functionalities and corner cases"
	"Docs/mm/damon: misc readability improvements"
	"mm/damon: let DAMOS feeds and tame/auto-tune itself"

 - In the series "mm/mempolicy: weighted interleave mempolicy and sysfs
   extension" Rakie Kim has developed a new mempolicy interleaving
   policy wherein we allocate memory across nodes in a weighted fashion
   rather than uniformly. This is beneficial in heterogeneous memory
   environments appearing with CXL.

 - Christophe Leroy has contributed some cleanup and consolidation work
   against the ARM pagetable dumping code in the series "mm: ptdump:
   Refactor CONFIG_DEBUG_WX and check_wx_pages debugfs attribute".

 - Luis Chamberlain has added some additional xarray selftesting in the
   series "test_xarray: advanced API multi-index tests".

 - Muhammad Usama Anjum has reworked the selftest code to make its
   human-readable output conform to the TAP ("Test Anything Protocol")
   format. Amongst other things, this opens up the use of third-party
   tools to parse and process out selftesting results.

 - Ryan Roberts has added fork()-time PTE batching of THP ptes in the
   series "mm/memory: optimize fork() with PTE-mapped THP". Mainly
   targeted at arm64, this significantly speeds up fork() when the
   process has a large number of pte-mapped folios.

 - David Hildenbrand also gets in on the THP pte batching game in his
   series "mm/memory: optimize unmap/zap with PTE-mapped THP". It
   implements batching during munmap() and other pte teardown
   situations. The microbenchmark improvements are nice.

 - And in the series "Transparent Contiguous PTEs for User Mappings"
   Ryan Roberts further utilizes arm's pte's contiguous bit ("contpte
   mappings"). Kernel build times on arm64 improved nicely. Ryan's
   series "Address some contpte nits" provides some followup work.

 - In the series "mm/hugetlb: Restore the reservation" Breno Leitao has
   fixed an obscure hugetlb race which was causing unnecessary page
   faults. He has also added a reproducer under the selftest code.

 - In the series "selftests/mm: Output cleanups for the compaction
   test", Mark Brown did what the title claims.

 - Kinsey Ho has added the series "mm/mglru: code cleanup and
   refactoring".

 - Even more zswap material from Nhat Pham. The series "fix and extend
   zswap kselftests" does as claimed.

 - In the series "Introduce cpu_dcache_is_aliasing() to fix DAX
   regression" Mathieu Desnoyers has cleaned up and fixed rather a mess
   in our handling of DAX on archiecctures which have virtually aliasing
   data caches. The arm architecture is the main beneficiary.

 - Lokesh Gidra's series "per-vma locks in userfaultfd" provides
   dramatic improvements in worst-case mmap_lock hold times during
   certain userfaultfd operations.

 - Some page_owner enhancements and maintenance work from Oscar Salvador
   in his series

	"page_owner: print stacks and their outstanding allocations"
	"page_owner: Fixup and cleanup"

 - Uladzislau Rezki has contributed some vmalloc scalability
   improvements in his series "Mitigate a vmap lock contention". It
   realizes a 12x improvement for a certain microbenchmark.

 - Some kexec/crash cleanup work from Baoquan He in the series "Split
   crash out from kexec and clean up related config items".

 - Some zsmalloc maintenance work from Chengming Zhou in the series

	"mm/zsmalloc: fix and optimize objects/page migration"
	"mm/zsmalloc: some cleanup for get/set_zspage_mapping()"

 - Zi Yan has taught the MM to perform compaction on folios larger than
   order=0. This a step along the path to implementaton of the merging
   of large anonymous folios. The series is named "Enable >0 order folio
   memory compaction".

 - Christoph Hellwig has done quite a lot of cleanup work in the
   pagecache writeback code in his series "convert write_cache_pages()
   to an iterator".

 - Some modest hugetlb cleanups and speedups in Vishal Moola's series
   "Handle hugetlb faults under the VMA lock".

 - Zi Yan has changed the page splitting code so we can split huge pages
   into sizes other than order-0 to better utilize large folios. The
   series is named "Split a folio to any lower order folios".

 - David Hildenbrand has contributed the series "mm: remove
   total_mapcount()", a cleanup.

 - Matthew Wilcox has sought to improve the performance of bulk memory
   freeing in his series "Rearrange batched folio freeing".

 - Gang Li's series "hugetlb: parallelize hugetlb page init on boot"
   provides large improvements in bootup times on large machines which
   are configured to use large numbers of hugetlb pages.

 - Matthew Wilcox's series "PageFlags cleanups" does that.

 - Qi Zheng's series "minor fixes and supplement for ptdesc" does that
   also. S390 is affected.

 - Cleanups to our pagemap utility functions from Peter Xu in his series
   "mm/treewide: Replace pXd_large() with pXd_leaf()".

 - Nico Pache has fixed a few things with our hugepage selftests in his
   series "selftests/mm: Improve Hugepage Test Handling in MM
   Selftests".

 - Also, of course, many singleton patches to many things. Please see
   the individual changelogs for details.

* tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (435 commits)
  mm/zswap: remove the memcpy if acomp is not sleepable
  crypto: introduce: acomp_is_async to expose if comp drivers might sleep
  memtest: use {READ,WRITE}_ONCE in memory scanning
  mm: prohibit the last subpage from reusing the entire large folio
  mm: recover pud_leaf() definitions in nopmd case
  selftests/mm: skip the hugetlb-madvise tests on unmet hugepage requirements
  selftests/mm: skip uffd hugetlb tests with insufficient hugepages
  selftests/mm: dont fail testsuite due to a lack of hugepages
  mm/huge_memory: skip invalid debugfs new_order input for folio split
  mm/huge_memory: check new folio order when split a folio
  mm, vmscan: retry kswapd's priority loop with cache_trim_mode off on failure
  mm: add an explicit smp_wmb() to UFFDIO_CONTINUE
  mm: fix list corruption in put_pages_list
  mm: remove folio from deferred split list before uncharging it
  filemap: avoid unnecessary major faults in filemap_fault()
  mm,page_owner: drop unnecessary check
  mm,page_owner: check for null stack_record before bumping its refcount
  mm: swap: fix race between free_swap_and_cache() and swapoff()
  mm/treewide: align up pXd_leaf() retval across archs
  mm/treewide: drop pXd_large()
  ...
2024-03-14 17:43:30 -07:00
Linus Torvalds
ce0c1c9265 Merge tag 'modules-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux
Pull modules updates from Luis Chamberlain:
 "Christophe Leroy did most of the work on this release, first with a
  few cleanups on CONFIG_STRICT_KERNEL_RWX and ending with error
  handling for when set_memory_XX() can fail.

  This is part of a larger effort to clean up all these callers which
  can fail, modules is just part of it"

* tag 'modules-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  module: Don't ignore errors from set_memory_XX()
  lib/test_kmod: fix kernel-doc warnings
  powerpc: Simplify strict_kernel_rwx_enabled()
  modules: Remove #ifdef CONFIG_STRICT_MODULE_RWX around rodata_enabled
  init: Declare rodata_enabled and mark_rodata_ro() at all time
  module: Change module_enable_{nx/x/ro}() to more explicit names
  module: Use set_memory_rox()
2024-03-13 12:40:58 -07:00
Linus Torvalds
fcc196579a Merge tag 'x86-cleanups-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cleanups from Ingo Molnar:
 "Misc cleanups, including a large series from Thomas Gleixner to cure
  sparse warnings"

* tag 'x86-cleanups-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/nmi: Drop unused declaration of proc_nmi_enabled()
  x86/callthunks: Use EXPORT_PER_CPU_SYMBOL_GPL() for per CPU variables
  x86/cpu: Provide a declaration for itlb_multihit_kvm_mitigation
  x86/cpu: Use EXPORT_PER_CPU_SYMBOL_GPL() for x86_spec_ctrl_current
  x86/uaccess: Add missing __force to casts in __access_ok() and valid_user_address()
  x86/percpu: Cure per CPU madness on UP
  smp: Consolidate smp_prepare_boot_cpu()
  x86/msr: Add missing __percpu annotations
  x86/msr: Prepare for including <linux/percpu.h> into <asm/msr.h>
  perf/x86/amd/uncore: Fix __percpu annotation
  x86/nmi: Remove an unnecessary IS_ENABLED(CONFIG_SMP)
  x86/apm_32: Remove dead function apm_get_battery_status()
  x86/insn-eval: Fix function param name in get_eff_addr_sib()
2024-03-11 19:37:56 -07:00
Linus Torvalds
ca7e917769 Merge tag 'x86-apic-2024-03-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 APIC updates from Thomas Gleixner:
 "Rework of APIC enumeration and topology evaluation.

  The current implementation has a couple of shortcomings:

   - It fails to handle hybrid systems correctly.

   - The APIC registration code which handles CPU number assignents is
     in the middle of the APIC code and detached from the topology
     evaluation.

   - The various mechanisms which enumerate APICs, ACPI, MPPARSE and
     guest specific ones, tweak global variables as they see fit or in
     case of XENPV just hack around the generic mechanisms completely.

   - The CPUID topology evaluation code is sprinkled all over the vendor
     code and reevaluates global variables on every hotplug operation.

   - There is no way to analyze topology on the boot CPU before bringing
     up the APs. This causes problems for infrastructure like PERF which
     needs to size certain aspects upfront or could be simplified if
     that would be possible.

   - The APIC admission and CPU number association logic is
     incomprehensible and overly complex and needs to be kept around
     after boot instead of completing this right after the APIC
     enumeration.

  This update addresses these shortcomings with the following changes:

   - Rework the CPUID evaluation code so it is common for all vendors
     and provides information about the APIC ID segments in a uniform
     way independent of the number of segments (Thread, Core, Module,
     ..., Die, Package) so that this information can be computed instead
     of rewriting global variables of dubious value over and over.

   - A few cleanups and simplifcations of the APIC, IO/APIC and related
     interfaces to prepare for the topology evaluation changes.

   - Seperation of the parser stages so the early evaluation which tries
     to find the APIC address can be seperately overridden from the late
     evaluation which enumerates and registers the local APIC as further
     preparation for sanitizing the topology evaluation.

   - A new registration and admission logic which

       - encapsulates the inner workings so that parsers and guest logic
         cannot longer fiddle in it

       - uses the APIC ID segments to build topology bitmaps at
         registration time

       - provides a sane admission logic

       - allows to detect the crash kernel case, where CPU0 does not run
         on the real BSP, automatically. This is required to prevent
         sending INIT/SIPI sequences to the real BSP which would reset
         the whole machine. This was so far handled by a tedious command
         line parameter, which does not even work in nested crash
         scenarios.

       - Associates CPU number after the enumeration completed and
         prevents the late registration of APICs, which was somehow
         tolerated before.

   - Converting all parsers and guest enumeration mechanisms over to the
     new interfaces.

     This allows to get rid of all global variable tweaking from the
     parsers and enumeration mechanisms and sanitizes the XEN[PV]
     handling so it can use CPUID evaluation for the first time.

   - Mopping up existing sins by taking the information from the APIC ID
     segment bitmaps.

     This evaluates hybrid systems correctly on the boot CPU and allows
     for cleanups and fixes in the related drivers, e.g. PERF.

  The series has been extensively tested and the minimal late fallout
  due to a broken ACPI/MADT table has been addressed by tightening the
  admission logic further"

* tag 'x86-apic-2024-03-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (76 commits)
  x86/topology: Ignore non-present APIC IDs in a present package
  x86/apic: Build the x86 topology enumeration functions on UP APIC builds too
  smp: Provide 'setup_max_cpus' definition on UP too
  smp: Avoid 'setup_max_cpus' namespace collision/shadowing
  x86/bugs: Use fixed addressing for VERW operand
  x86/cpu/topology: Get rid of cpuinfo::x86_max_cores
  x86/cpu/topology: Provide __num_[cores|threads]_per_package
  x86/cpu/topology: Rename topology_max_die_per_package()
  x86/cpu/topology: Rename smp_num_siblings
  x86/cpu/topology: Retrieve cores per package from topology bitmaps
  x86/cpu/topology: Use topology logical mapping mechanism
  x86/cpu/topology: Provide logical pkg/die mapping
  x86/cpu/topology: Simplify cpu_mark_primary_thread()
  x86/cpu/topology: Mop up primary thread mask handling
  x86/cpu/topology: Use topology bitmaps for sizing
  x86/cpu/topology: Let XEN/PV use topology from CPUID/MADT
  x86/xen/smp_pv: Count number of vCPUs early
  x86/cpu/topology: Assign hotpluggable CPUIDs during init
  x86/cpu/topology: Reject unknown APIC IDs on ACPI hotplug
  x86/topology: Add a mechanism to track topology via APIC IDs
  ...
2024-03-11 15:45:55 -07:00
Linus Torvalds
ff887eb07c Merge tag 'wq-for-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue updates from Tejun Heo:
 "This cycle, a lot of workqueue changes including some that are
  significant and invasive.

   - During v6.6 cycle, unbound workqueues were updated so that they are
     more topology aware and flexible, which among other things improved
     workqueue behavior on modern multi-L3 CPUs. In the process, commit
     636b927eba ("workqueue: Make unbound workqueues to use per-cpu
     pool_workqueues") switched unbound workqueues to use per-CPU
     frontend pool_workqueues as a part of increasing front-back mapping
     flexibility.

     An unwelcome side effect of this change was that this made max
     concurrency enforcement per-CPU blowing up the maximum number of
     allowed concurrent executions. I incorrectly assumed that this
     wouldn't cause practical problems as most unbound workqueue users
     are self-regulate max concurrency; however, there definitely are
     which don't (e.g. on IO paths) and the drastic increase in the
     allowed max concurrency led to noticeable perf regressions in some
     use cases.

     This is now addressed by separating out max concurrency enforcement
     to a separate struct - wq_node_nr_active - which makes @max_active
     consistently mean system-wide max concurrency regardless of the
     number of CPUs or (finally) NUMA nodes. This is a rather invasive
     and, in places, a bit clunky; however, the clunkiness rises from
     the the inherent requirement to handle the disagreement between the
     execution locality domain and max concurrency enforcement domain on
     some modern machines.

     See commit 5797b1c189 ("workqueue: Implement system-wide
     nr_active enforcement for unbound workqueues") for more details.

   - BH workqueue support is added.

     They are similar to per-CPU workqueues but execute work items in
     the softirq context. This is expected to replace tasklet. However,
     currently, it's missing the ability to disable and enable work
     items which is needed to convert many tasklet users. To avoid
     crowding this merge window too much, this will be included in the
     next merge window. A separate pull request will be sent for the
     couple conversion patches that are currently pending.

   - Waiman plugged a long-standing hole in workqueue CPU isolation
     where ordered workqueues didn't follow wq_unbound_cpumask updates.
     Ordered workqueues now follow the same rules as other unbound
     workqueues.

   - More CPU isolation improvements: Juri fixed another deficit in
     workqueue isolation where unbound rescuers don't respect
     wq_unbound_cpumask. Leonardo fixed delayed_work timers firing on
     isolated CPUs.

   - Other misc changes"

* tag 'wq-for-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (54 commits)
  workqueue: Drain BH work items on hot-unplugged CPUs
  workqueue: Introduce from_work() helper for cleaner callback declarations
  workqueue: Control intensive warning threshold through cmdline
  workqueue: Make @flags handling consistent across set_work_data() and friends
  workqueue: Remove clear_work_data()
  workqueue: Factor out work_grab_pending() from __cancel_work_sync()
  workqueue: Clean up enum work_bits and related constants
  workqueue: Introduce work_cancel_flags
  workqueue: Use variable name irq_flags for saving local irq flags
  workqueue: Reorganize flush and cancel[_sync] functions
  workqueue: Rename __cancel_work_timer() to __cancel_timer_sync()
  workqueue: Use rcu_read_lock_any_held() instead of rcu_read_lock_held()
  workqueue: Cosmetic changes
  workqueue, irq_work: Build fix for !CONFIG_IRQ_WORK
  workqueue: Fix queue_work_on() with BH workqueues
  async: Use a dedicated unbound workqueue with raised min_active
  workqueue: Implement workqueue_set_min_active()
  workqueue: Fix kernel-doc comment of unplug_oldest_pwq()
  workqueue: Bind unbound workqueue rescuer to wq_unbound_cpumask
  kernel/workqueue: Let rescuers follow unbound wq cpumask changes
  ...
2024-03-11 12:50:42 -07:00
Changbin Du
8f8cd6c0a4 modules: wait do_free_init correctly
The synchronization here is to ensure the ordering of freeing of a module
init so that it happens before W+X checking.  It is worth noting it is not
that the freeing was not happening, it is just that our sanity checkers
raced against the permission checkers which assume init memory is already
gone.

Commit 1a7b7d9220 ("modules: Use vmalloc special flag") moved calling
do_free_init() into a global workqueue instead of relying on it being
called through call_rcu(..., do_free_init), which used to allowed us call
do_free_init() asynchronously after the end of a subsequent grace period. 
The move to a global workqueue broke the gaurantees for code which needed
to be sure the do_free_init() would complete with rcu_barrier().  To fix
this callers which used to rely on rcu_barrier() must now instead use
flush_work(&init_free_wq).

Without this fix, we still could encounter false positive reports in W+X
checking since the rcu_barrier() here can not ensure the ordering now.

Even worse, the rcu_barrier() can introduce significant delay.  Eric
Chanudet reported that the rcu_barrier introduces ~0.1s delay on a
PREEMPT_RT kernel.

  [    0.291444] Freeing unused kernel memory: 5568K
  [    0.402442] Run /sbin/init as init process

With this fix, the above delay can be eliminated.

Link: https://lkml.kernel.org/r/20240227023546.2490667-1-changbin.du@huawei.com
Fixes: 1a7b7d9220 ("modules: Use vmalloc special flag")
Signed-off-by: Changbin Du <changbin.du@huawei.com>
Tested-by: Eric Chanudet <echanude@redhat.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Xiaoyi Su <suxiaoyi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-03-04 17:01:27 -08:00
Thomas Gleixner
712610725c smp: Consolidate smp_prepare_boot_cpu()
There is no point in having seven architectures implementing the same empty
stub.

Provide a weak function in the init code and remove the stubs.

This also allows to utilize the function on UP which is required to
sanitize the per CPU handling on X86 UP.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240304005104.567671691@linutronix.de
2024-03-04 12:01:54 +01:00