This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
The mapping VMA address is saved in VAS window struct when the
paste address is mapped. This VMA address is used during migration
to unmap the paste address if the window is active. The paste
address mapping will be removed when the window is closed or with
the munmap(). But the VMA address in the VAS window is not updated
with munmap() which is causing invalid access during migration.
The KASAN report shows:
[16386.254991] BUG: KASAN: slab-use-after-free in reconfig_close_windows+0x1a0/0x4e8
[16386.255043] Read of size 8 at addr c00000014a819670 by task drmgr/696928
[16386.255096] CPU: 29 UID: 0 PID: 696928 Comm: drmgr Kdump: loaded Tainted: G B 6.11.0-rc5-nxgzip #2
[16386.255128] Tainted: [B]=BAD_PAGE
[16386.255148] Hardware name: IBM,9080-HEX Power11 (architected) 0x820200 0xf000007 of:IBM,FW1110.00 (NH1110_016) hv:phyp pSeries
[16386.255181] Call Trace:
[16386.255202] [c00000016b297660] [c0000000018ad0ac] dump_stack_lvl+0x84/0xe8 (unreliable)
[16386.255246] [c00000016b297690] [c0000000006e8a90] print_report+0x19c/0x764
[16386.255285] [c00000016b297760] [c0000000006e9490] kasan_report+0x128/0x1f8
[16386.255309] [c00000016b297880] [c0000000006eb5c8] __asan_load8+0xac/0xe0
[16386.255326] [c00000016b2978a0] [c00000000013f898] reconfig_close_windows+0x1a0/0x4e8
[16386.255343] [c00000016b297990] [c000000000140e58] vas_migration_handler+0x3a4/0x3fc
[16386.255368] [c00000016b297a90] [c000000000128848] pseries_migrate_partition+0x4c/0x4c4
...
[16386.256136] Allocated by task 696554 on cpu 31 at 16377.277618s:
[16386.256149] kasan_save_stack+0x34/0x68
[16386.256163] kasan_save_track+0x34/0x80
[16386.256175] kasan_save_alloc_info+0x58/0x74
[16386.256196] __kasan_slab_alloc+0xb8/0xdc
[16386.256209] kmem_cache_alloc_noprof+0x200/0x3d0
[16386.256225] vm_area_alloc+0x44/0x150
[16386.256245] mmap_region+0x214/0x10c4
[16386.256265] do_mmap+0x5fc/0x750
[16386.256277] vm_mmap_pgoff+0x14c/0x24c
[16386.256292] ksys_mmap_pgoff+0x20c/0x348
[16386.256303] sys_mmap+0xd0/0x160
...
[16386.256350] Freed by task 0 on cpu 31 at 16386.204848s:
[16386.256363] kasan_save_stack+0x34/0x68
[16386.256374] kasan_save_track+0x34/0x80
[16386.256384] kasan_save_free_info+0x64/0x10c
[16386.256396] __kasan_slab_free+0x120/0x204
[16386.256415] kmem_cache_free+0x128/0x450
[16386.256428] vm_area_free_rcu_cb+0xa8/0xd8
[16386.256441] rcu_do_batch+0x2c8/0xcf0
[16386.256458] rcu_core+0x378/0x3c4
[16386.256473] handle_softirqs+0x20c/0x60c
[16386.256495] do_softirq_own_stack+0x6c/0x88
[16386.256509] do_softirq_own_stack+0x58/0x88
[16386.256521] __irq_exit_rcu+0x1a4/0x20c
[16386.256533] irq_exit+0x20/0x38
[16386.256544] interrupt_async_exit_prepare.constprop.0+0x18/0x2c
...
[16386.256717] Last potentially related work creation:
[16386.256729] kasan_save_stack+0x34/0x68
[16386.256741] __kasan_record_aux_stack+0xcc/0x12c
[16386.256753] __call_rcu_common.constprop.0+0x94/0xd04
[16386.256766] vm_area_free+0x28/0x3c
[16386.256778] remove_vma+0xf4/0x114
[16386.256797] do_vmi_align_munmap.constprop.0+0x684/0x870
[16386.256811] __vm_munmap+0xe0/0x1f8
[16386.256821] sys_munmap+0x54/0x6c
[16386.256830] system_call_exception+0x1a0/0x4a0
[16386.256841] system_call_vectored_common+0x15c/0x2ec
[16386.256868] The buggy address belongs to the object at c00000014a819670
which belongs to the cache vm_area_struct of size 168
[16386.256887] The buggy address is located 0 bytes inside of
freed 168-byte region [c00000014a819670, c00000014a819718)
[16386.256915] The buggy address belongs to the physical page:
[16386.256928] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14a81
[16386.256950] memcg:c0000000ba430001
[16386.256961] anon flags: 0x43ffff800000000(node=4|zone=0|lastcpupid=0x7ffff)
[16386.256975] page_type: 0xfdffffff(slab)
[16386.256990] raw: 043ffff800000000 c00000000501c080 0000000000000000 5deadbee00000001
[16386.257003] raw: 0000000000000000 00000000011a011a 00000001fdffffff c0000000ba430001
[16386.257018] page dumped because: kasan: bad access detected
This patch adds close() callback in vas_vm_ops vm_operations_struct
which will be executed during munmap() before freeing VMA. The VMA
address in the VAS window is set to NULL after holding the window
mmap_mutex.
Fixes: 37e6764895 ("powerpc/pseries/vas: Add VAS migration handler")
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20241214051758.997759-1-haren@linux.ibm.com
The VAS open window call prints error message and returns -EBUSY
after the migration suspend event initiated and until the resume
event completed on the destination system. It can cause the log
buffer filled with these error messages if the user space issues
continuous open window calls. Similar case even for DLPAR CPU
remove event when no credits are available until the credits are
freed or with the other DLPAR CPU add event.
So changes in the patch to use pr_err_ratelimited() instead of
pr_err() to display open window failure and not-available credits
error messages.
Use pr_fmt() and make the corresponding changes to have the
consistencein prefix all pr_*() messages (vas-api.c).
Fixes: 37e6764895 ("powerpc/pseries/vas: Add VAS migration handler")
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
[mpe: Use "vas-api" as the prefix to match the file name.]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231019215033.1335251-1-haren@linux.ibm.com
The paste address mapping is done with mmap() after the window is
opened with ioctl. The partition has to close VAS windows in the
hypervisor if it lost credits due to DLPAR core removal. But the
kernel marks these windows inactive until the previously lost
credits are available later. If the window is inactive due to
DLPAR after this mmap(), the paste instruction returns failure
until the the OS reopens this window again.
Before the user space issuing mmap(), there is a possibility of
happening DLPAR core removal event which causes the corresponding
window inactive. So if the window is not active, return mmap()
failure with -EACCES and expects the user space reissue mmap()
when the window is active or open a new window when the credit
is available.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/bbb203c26b324534e25658cb1dbbcb5160a2f93a.camel@linux.ibm.com
The VAS window may not be active if the system looses credits and
the NX generates page fault when it receives request on unmap
paste address.
The kernel handles the fault by remap new paste address if the
window is active again, Otherwise return the paste instruction
failure if the executed instruction that caused the fault was
a paste.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/492b9aefd593061d51dda67ee4d2fc449c000dce.camel@linux.ibm.com
The user space opens VAS windows and issues NX requests by pasting
CRB on the corresponding paste address mmap. When the system lost
credits due to core removal, the kernel has to close the window in
the hypervisor and make the window inactive by unmapping this paste
address. Also the OS has to handle NX request page faults if the user
space issue NX requests.
This handler maps the new paste address with the same VMA when the
window is active again (due to core add with DLPAR). Otherwise
returns paste failure.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3956e1c1fdfde69127055ff1c0256c7d71104030.camel@linux.ibm.com
(!ptr && !ptr->foo) strikes again. :)
The expression (!ptr && !ptr->foo) is bogus and in case ptr is NULL,
it leads to a NULL pointer dereference: ptr->foo.
Fix this by converting && to ||
This issue was detected with the help of Coccinelle, and audited and
fixed manually.
Fixes: 1a0d0d5ed5 ("powerpc/vas: Add platform specific user window operations")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211015050345.GA1161918@embeddedor
