Pull non-MM updates from Andrew Morton:
- "panic: sys_info: Refactor and fix a potential issue" (Andy Shevchenko)
fixes a build issue and does some cleanup in ib/sys_info.c
- "Implement mul_u64_u64_div_u64_roundup()" (David Laight)
enhances the 64-bit math code on behalf of a PWM driver and beefs up
the test module for these library functions
- "scripts/gdb/symbols: make BPF debug info available to GDB" (Ilya Leoshkevich)
makes BPF symbol names, sizes, and line numbers available to the GDB
debugger
- "Enable hung_task and lockup cases to dump system info on demand" (Feng Tang)
adds a sysctl which can be used to cause additional info dumping when
the hung-task and lockup detectors fire
- "lib/base64: add generic encoder/decoder, migrate users" (Kuan-Wei Chiu)
adds a general base64 encoder/decoder to lib/ and migrates several
users away from their private implementations
- "rbree: inline rb_first() and rb_last()" (Eric Dumazet)
makes TCP a little faster
- "liveupdate: Rework KHO for in-kernel users" (Pasha Tatashin)
reworks the KEXEC Handover interfaces in preparation for Live Update
Orchestrator (LUO), and possibly for other future clients
- "kho: simplify state machine and enable dynamic updates" (Pasha Tatashin)
increases the flexibility of KEXEC Handover. Also preparation for LUO
- "Live Update Orchestrator" (Pasha Tatashin)
is a major new feature targeted at cloud environments. Quoting the
cover letter:
This series introduces the Live Update Orchestrator, a kernel
subsystem designed to facilitate live kernel updates using a
kexec-based reboot. This capability is critical for cloud
environments, allowing hypervisors to be updated with minimal
downtime for running virtual machines. LUO achieves this by
preserving the state of selected resources, such as memory,
devices and their dependencies, across the kernel transition.
As a key feature, this series includes support for preserving
memfd file descriptors, which allows critical in-memory data, such
as guest RAM or any other large memory region, to be maintained in
RAM across the kexec reboot.
Mike Rappaport merits a mention here, for his extensive review and
testing work.
- "kexec: reorganize kexec and kdump sysfs" (Sourabh Jain)
moves the kexec and kdump sysfs entries from /sys/kernel/ to
/sys/kernel/kexec/ and adds back-compatibility symlinks which can
hopefully be removed one day
- "kho: fixes for vmalloc restoration" (Mike Rapoport)
fixes a BUG which was being hit during KHO restoration of vmalloc()
regions
* tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (139 commits)
calibrate: update header inclusion
Reinstate "resource: avoid unnecessary lookups in find_next_iomem_res()"
vmcoreinfo: track and log recoverable hardware errors
kho: fix restoring of contiguous ranges of order-0 pages
kho: kho_restore_vmalloc: fix initialization of pages array
MAINTAINERS: TPM DEVICE DRIVER: update the W-tag
init: replace simple_strtoul with kstrtoul to improve lpj_setup
KHO: fix boot failure due to kmemleak access to non-PRESENT pages
Documentation/ABI: new kexec and kdump sysfs interface
Documentation/ABI: mark old kexec sysfs deprecated
kexec: move sysfs entries to /sys/kernel/kexec
test_kho: always print restore status
kho: free chunks using free_page() instead of kfree()
selftests/liveupdate: add kexec test for multiple and empty sessions
selftests/liveupdate: add simple kexec-based selftest for LUO
selftests/liveupdate: add userspace API selftests
docs: add documentation for memfd preservation via LUO
mm: memfd_luo: allow preserving memfd
liveupdate: luo_file: add private argument to store runtime state
mm: shmem: export some functions to internal.h
...
Assert that we correctly merge VMAs containing VM_SOFTDIRTY flags now that
we correctly handle these as sticky.
In order to do so, we have to account for the fact the pagemap interface
checks soft dirty PTEs and additionally that newly merged VMAs are marked
VM_SOFTDIRTY.
We do this by using use unfaulted anon VMAs, establishing one and clearing
references on that one, before establishing another and merging the two
before checking that soft-dirty is propagated as expected.
We check that this functions correctly with mremap() and mprotect() as
sample cases, because VMA merge of adjacent newly mapped VMAs will
automatically be made soft-dirty due to existing logic which does so.
We are therefore exercising other means of merging VMAs.
Link: https://lkml.kernel.org/r/d5a0f735783fb4f30a604f570ede02ccc5e29be9.1763399675.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Andrey Vagin <avagin@gmail.com>
Cc: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The test will fail as below on x86_64 with cpu la57 support (will skip if
no la57 support). Note, the test requries nr_hugepages to be set first.
# running bash ./va_high_addr_switch.sh
# -------------------------------------
# mmap(addr_switch_hint - pagesize, pagesize): 0x7f55b60fa000 - OK
# mmap(addr_switch_hint - pagesize, (2 * pagesize)): 0x7f55b60f9000 - OK
# mmap(addr_switch_hint, pagesize): 0x800000000000 - OK
# mmap(addr_switch_hint, 2 * pagesize, MAP_FIXED): 0x800000000000 - OK
# mmap(NULL): 0x7f55b60f9000 - OK
# mmap(low_addr): 0x40000000 - OK
# mmap(high_addr): 0x1000000000000 - OK
# mmap(high_addr) again: 0xffff55b6136000 - OK
# mmap(high_addr, MAP_FIXED): 0x1000000000000 - OK
# mmap(-1): 0xffff55b6134000 - OK
# mmap(-1) again: 0xffff55b6132000 - OK
# mmap(addr_switch_hint - pagesize, pagesize): 0x7f55b60fa000 - OK
# mmap(addr_switch_hint - pagesize, 2 * pagesize): 0x7f55b60f9000 - OK
# mmap(addr_switch_hint - pagesize/2 , 2 * pagesize): 0x7f55b60f7000 - OK
# mmap(addr_switch_hint, pagesize): 0x800000000000 - OK
# mmap(addr_switch_hint, 2 * pagesize, MAP_FIXED): 0x800000000000 - OK
# mmap(NULL, MAP_HUGETLB): 0x7f55b5c00000 - OK
# mmap(low_addr, MAP_HUGETLB): 0x40000000 - OK
# mmap(high_addr, MAP_HUGETLB): 0x1000000000000 - OK
# mmap(high_addr, MAP_HUGETLB) again: 0xffff55b5e00000 - OK
# mmap(high_addr, MAP_FIXED | MAP_HUGETLB): 0x1000000000000 - OK
# mmap(-1, MAP_HUGETLB): 0x7f55b5c00000 - OK
# mmap(-1, MAP_HUGETLB) again: 0x7f55b5a00000 - OK
# mmap(addr_switch_hint - pagesize, 2*hugepagesize, MAP_HUGETLB): 0x800000000000 - FAILED
# mmap(addr_switch_hint , 2*hugepagesize, MAP_FIXED | MAP_HUGETLB): 0x800000000000 - OK
# [FAIL]
addr_switch_hint is defined as DFEFAULT_MAP_WINDOW in the failed test (for
x86_64, DFEFAULT_MAP_WINDOW is defined as (1UL<<47) - pagesize) in 64 bit.
Before commit cc92882ee2 ("mm: drop hugetlb_get_unmapped_area{_*}
functions"), for x86_64 hugetlb_get_unmapped_area() is handled in arch
code arch/x86/mm/hugetlbpage.c and addr is checked with
map_address_hint_valid() after align with 'addr &= huge_page_mask(h)'
which is a round down way, and it will fail the check because the addr is
within the DEFAULT_MAP_WINDOW but (addr + len) is above the
DFEFAULT_MAP_WINDOW. So it wil go through the
hugetlb_get_unmmaped_area_top_down() to find an area within the
DFEFAULT_MAP_WINDOW.
After commit cc92882ee2 ("mm: drop hugetlb_get_unmapped_area{_*}
functions"). The addr hint for hugetlb_get_unmmaped_area() will be
rounded up and aligned to hugepage size with ALIGN() for all arches. And
after the align, the addr will be above the default MAP_DEFAULT_WINDOW,
and the map_addresshint_valid() check will pass because both aligned addr
(addr0) and (addr + len) are above the DEFAULT_MAP_WINDOW, and the aligned
hint address (0x800000000000) is returned as an suitable gap is found
there, in arch_get_unmapped_area_topdown().
To still cover the case that addr is within the DEFAULT_MAP_WINDOW, and
addr + len is above the DFEFAULT_MAP_WINDOW, change to choose the last
hugepage aligned address within the DEFAULT_MAP_WINDOW as the hint addr,
and the addr + len (2 hugepages) will be one hugepage above the
DEFAULT_MAP_WINDOW. An aligned address won't be affected by the page
round up or round down from kernel, so it's determistic.
Link: https://lkml.kernel.org/r/20250912013711.3002969-4-chuhu@redhat.com
Fixes: cc92882ee2 ("mm: drop hugetlb_get_unmapped_area{_*} functions")
Signed-off-by: Chunyu Hu <chuhu@redhat.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Alloc hugepages in the test internally, so we don't fully rely on the
run_vmtests.sh. If run_vmtests.sh does that great, free hugepages is
enough for being used to run the test, leave it as it is, otherwise setup
the hugepages in the test.
Save the original nr_hugepages value and restore it after test finish, so
leave a stable test envronment.
Link: https://lkml.kernel.org/r/20250912013711.3002969-3-chuhu@redhat.com
Signed-off-by: Chunyu Hu <chuhu@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Fix va_high_addr_switch.sh test failure", v3.
These three patches fix the va_high_addr_switch.sh test failure on x86_64.
Patch 1 fixes the hugepage setup issue that nr_hugepages is reset too
early in run_vmtests.sh and break the later va_high_addr_switch testing.
Patch 2 adds hugepage setup in va_high_addr_switch test, so that it can
still work if vm_runtests.sh changes the hugepage setup someday.
Patch 3 fixes the test failure caused by the hint addr align method change
in hugetlb_get_unmapped_area().
This patch (of 3):
The nr_hugepgs variable is used to keep the original nr_hugepages at the
hugepage setup step at test beginning. After userfaultfd test, a cleaup
is executed, both /sys/kernel/mm/hugepages/hugepages-*/nr_hugepages and
/proc/sys//vm/nr_hugepages are reset to 'original' value before
userfaultfd test starts.
Issue here is the value used to restore /proc/sys/vm/nr_hugepages is
nr_hugepgs which is the initial value before the vm_runtests.sh runs, not
the value before userfaultfd test starts. 'va_high_addr_swith.sh' tests
runs after that will possibly see no hugepages available for test, and got
EINVAL when mmap(HUGETLB), making the result invalid.
And before pkey tests, nr_hugepgs is changed to be used as a temp variable
to save nr_hugepages before pkey test, and restore it after pkey tests
finish. The original nr_hugepages value is not tracked anymore, so no way
to restore it after all tests finish.
Add a new variable orig_nr_hugepgs to save the original nr_hugepages, and
and restore it to nr_hugepages after all tests finish. And change to use
the nr_hugepgs variable to save the /proc/sys/vm/nr_hugeages after
hugepage setup, it's also the value before userfaultfd test starts, and
the correct value to be restored after userfaultfd finishes. The
va_high_addr_switch.sh broken will be resolved.
Link: https://lkml.kernel.org/r/20250912013711.3002969-1-chuhu@redhat.com
Link: https://lkml.kernel.org/r/20250912013711.3002969-2-chuhu@redhat.com
Signed-off-by: Chunyu Hu <chuhu@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is room for improvement, so let's clean up a bit:
(1) Define "4" as a constant.
(2) SKIP if we fail to allocate all THPs (e.g., fragmented) and add
recovery code for all other failure cases: no need to exit the test.
(3) Rename "len" to thp_area_size, and "one_page" to "thp_area".
(4) Allocate a new area "page_area" into which we will mremap the
pages; add "page_area_size". Now we can easily merge the two
mremap instances into a single one.
(5) Iterate THPs instead of bytes when checking for missed THPs after
mremap.
(6) Rename "pte_mapped2" to "tmp", used to verify mremap(MAP_FIXED)
result.
(7) Split the corruption test from the failed-split test, so we can just
iterate bytes vs. thps naturally.
(8) Extend comments and clarify why we are using mremap in the first
place.
Link: https://lkml.kernel.org/r/20250903070253.34556-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "selftests/mm: split_huge_page_test: split_pte_mapped_thp
improvements", v2.
One fix for occasional failures I found while testing and a bunch of
cleanups that should make that test easier to digest.
This patch (of 2):
When checking for actual tail or head pages of a folio, we must make sure
that the KPF_COMPOUND_HEAD/KPF_COMPOUND_TAIL flag is paired with KPF_THP.
For example, if we have another large folio after our large folio in
physical memory, our "pfn_flags & (KPF_THP | KPF_COMPOUND_TAIL)" would
trigger even though it's actually a head page of the next folio.
If is_backed_by_folio() returns a wrong result, split_pte_mapped_thp() can
fail with "Some THPs are missing during mremap".
Fix it by checking for head/tail pages of folios properly. Add
folio_tail_flags/folio_head_flags to improve readability and use these
masks also when just testing for any compound page.
Link: https://lkml.kernel.org/r/20250903070253.34556-1-david@redhat.com
Link: https://lkml.kernel.org/r/20250903070253.34556-2-david@redhat.com
Fixes: 169b456b0162 ("selftests/mm: reimplement is_backed_by_thp() with more precise check")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "selftests/mm: uffd-stress fixes", v2.
This patchset ensures that the number of hugepages is correctly set in the
system so that the uffd-stress test does not fail due to the racy nature
of the test. Patch 1 changes the hugepage constraint in the
run_vmtests.sh script, whereas patch 2 changes the constraint in the test
itself.
This patch (of 2):
We observed uffd-stress selftest failure on arm64 and intermittent
failures on x86 too:
running ./uffd-stress hugetlb-private 128 32
bounces: 17, mode: rnd read, ERROR: UFFDIO_COPY error: -12 (errno=12, @uffd-common.c:617) [FAIL]
not ok 18 uffd-stress hugetlb-private 128 32 # exit=1
For this particular case, the number of free hugepages from run_vmtests.sh
will be 128, and the test will allocate 64 hugepages in the source
location. The stress() function will start spawning threads which will
operate on the destination location, triggering uffd-operations like
UFFDIO_COPY from src to dst, which means that we will require 64 more
hugepages for the dst location.
Let us observe the locking_thread() function. It will lock the mutex kept
at dst, triggering uffd-copy. Suppose that 127 (64 for src and 63 for
dst) hugepages have been reserved. In case of BOUNCE_RANDOM, it may
happen that two threads trying to lock the mutex at dst, try to do so at
the same hugepage number. If one thread succeeds in reserving the last
hugepage, then the other thread may fail in alloc_hugetlb_folio(),
returning -ENOMEM. I can confirm that this is indeed the case by this
hacky patch:
:--- a/mm/hugetlb.c
; +++ b/mm/hugetlb.c
; @@ -6929,6 +6929,11 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
;
; folio = alloc_hugetlb_folio(dst_vma, dst_addr, false);
; if (IS_ERR(folio)) {
; + pte_t *actual_pte = hugetlb_walk(dst_vma, dst_addr, PMD_SIZE);
; + if (actual_pte) {
; + ret = -EEXIST;
; + goto out;
; + }
; ret = -ENOMEM;
; goto out;
; }
This code path gets triggered indicating that the PMD at which one thread
is trying to map a hugepage, gets filled by a racing thread.
Therefore, instead of using freepgs to compute the amount of memory, use
freepgs - (min(32, nr_cpus) - 1), so that the test still has some extra
hugepages to use. The adjustment is a function of min(32, nr_cpus) - the
value of nr_parallel in the test - because in the worst case, nr_parallel
number of threads will try to map a hugepage on the same PMD, one will win
the allocation race, and the other nr_parallel - 1 threads will fail, so
we need extra nr_parallel - 1 hugepages to satisfy this request. Note
that, in case the adjusted value underflows, there is a check for the
number of free hugepages in the test itself, which will fail:
get_free_hugepages() < bytes / page_size A negative value will be passed
on to bytes which is of type size_t, thus the RHS will become a large
value and the check will fail, so we are safe.
Link: https://lkml.kernel.org/r/20250909061531.57272-1-dev.jain@arm.com
Link: https://lkml.kernel.org/r/20250909061531.57272-2-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The test will set the global system THP setting to never, madvise or
always depending on the fixture variant and the 2M setting to inherit
before it starts (and reset to original at teardown). The fixture setup
will also test if PR_SET_THP_DISABLE prctl call can be made with
PR_THP_DISABLE_EXCEPT_ADVISED and skip if it fails.
This tests if the process can:
- successfully get the policy to disable THPs expect for madvise.
- get hugepages only on MADV_HUGE and MADV_COLLAPSE if the global policy
is madvise/always and only with MADV_COLLAPSE if the global policy is
never.
- successfully reset the policy of the process.
- after reset, only get hugepages with:
- MADV_COLLAPSE when policy is set to never.
- MADV_HUGE and MADV_COLLAPSE when policy is set to madvise.
- always when policy is set to "always".
- never get a THP with MADV_NOHUGEPAGE.
- repeat the above tests in a forked process to make sure the policy is
carried across forks.
Test results:
./prctl_thp_disable
TAP version 13
1..12
ok 1 prctl_thp_disable_completely.never.nofork
ok 2 prctl_thp_disable_completely.never.fork
ok 3 prctl_thp_disable_completely.madvise.nofork
ok 4 prctl_thp_disable_completely.madvise.fork
ok 5 prctl_thp_disable_completely.always.nofork
ok 6 prctl_thp_disable_completely.always.fork
ok 7 prctl_thp_disable_except_madvise.never.nofork
ok 8 prctl_thp_disable_except_madvise.never.fork
ok 9 prctl_thp_disable_except_madvise.madvise.nofork
ok 10 prctl_thp_disable_except_madvise.madvise.fork
ok 11 prctl_thp_disable_except_madvise.always.nofork
ok 12 prctl_thp_disable_except_madvise.always.fork
[usamaarif642@gmail.com: return after executing test in child process]
Link: https://lkml.kernel.org/r/3dca2de4-9a6a-4efe-a86c-83f9509831fc@gmail.com
Link: https://lkml.kernel.org/r/20250815135549.130506-8-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yafang <laoar.shao@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In ksm_functional_tests, test_child_ksm() returned negative values to
indicate errors. However, when passed to exit(), these were interpreted
as large unsigned values (e.g, -2 became 254), leading to incorrect
handling in the parent process. As a result, some tests appeared to be
skipped or silently failed.
This patch changes test_child_ksm() to return positive error codes (1, 2,
3) and updates test_child_ksm_err() to interpret them correctly.
Additionally, test_prctl_fork_exec() now uses exit(4) after a failed
execv() to clearly signal exec failures. This ensures the parent
accurately detects and reports child process failures.
--------------
Before patch:
--------------
- [RUN] test_unmerge
ok 1 Pages were unmerged
...
- [RUN] test_prctl_fork
- No pages got merged
- [RUN] test_prctl_fork_exec
ok 7 PR_SET_MEMORY_MERGE value is inherited
...
Bail out! 1 out of 8 tests failed
- Planned tests != run tests (9 != 8)
- Totals: pass:7 fail:1 xfail:0 xpass:0 skip:0 error:0
--------------
After patch:
--------------
- [RUN] test_unmerge
ok 1 Pages were unmerged
...
- [RUN] test_prctl_fork
- No pages got merged
not ok 7 Merge in child failed
- [RUN] test_prctl_fork_exec
ok 8 PR_SET_MEMORY_MERGE value is inherited
...
Bail out! 2 out of 9 tests failed
- Totals: pass:7 fail:2 xfail:0 xpass:0 skip:0 error:0
Link: https://lkml.kernel.org/r/20250816040113.760010-6-aboorvad@linux.ibm.com
Fixes: 6c47de3be3 ("selftest/mm: ksm_functional_tests: extend test case for ksm fork/exec")
Co-developed-by: Donet Tom <donettom@linux.ibm.com>
Signed-off-by: Donet Tom <donettom@linux.ibm.com>
Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This patch fixes 2 issues.
1) After fork() in test_prctl_fork, the child process uses the file
descriptors from the parent process to read ksm_stat and
ksm_merging_pages. This results in incorrect values being read (parent
process ksm_stat and ksm_merging_pages will be read in child), causing
the test to fail.
This patch calls init_global_file_handles() in the child process to
ensure that the current process's file descriptors are used to read
ksm_stat and ksm_merging_pages.
2) All tests currently call ksm_merge to trigger page merging. To
ensure the system remains in a consistent state for subsequent tests,
it is better to call ksm_unmerge during the test cleanup phase
In the test_prctl_fork test, after a fork(), reading
ksm_merging_pages in the child process returns a non-zero value because
a previous test performed a merge, and the child's memory state is
inherited from the parent.
Although the child process calls ksm_unmerge, the ksm_merging_pages
counter in the parent is reset to zero, while the child's counter
remains unchanged. This discrepancy causes the test to fail.
To avoid this issue, each test should call ksm_unmerge during
cleanup to ensure the counter is reset and the system is in a clean
state for subsequent tests.
execv argument is an array of pointers to null-terminated strings. In
this patch we also added NULL in the execv argument.
Link: https://lkml.kernel.org/r/20250816040113.760010-4-aboorvad@linux.ibm.com
Fixes: 6c47de3be3 ("selftest/mm: ksm_functional_tests: extend test case for ksm fork/exec")
Co-developed-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
Signed-off-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
