linux-stable.git/lib, branch v6.18.27

lib: test_hmm: evict device pages on file close to avoid use-after-free

2026-05-07T04:12:00+00:00

[ Upstream commit 744dd97752ef1076a8d8672bb0d8aa2c7abc1144 ]

Patch series "Minor hmm_test fixes and cleanups".

Two bugfixes a cleanup for the HMM kernel selftests.  These were mostly
reported by Zenghui Yu with special thanks to Lorenzo for analysing and
pointing out the problems.

This patch (of 3):

When dmirror_fops_release() is called it frees the dmirror struct but
doesn't migrate device private pages back to system memory first.  This
leaves those pages with a dangling zone_device_data pointer to the freed
dmirror.

If a subsequent fault occurs on those pages (eg.  during coredump) the
dmirror_devmem_fault() callback dereferences the stale pointer causing a
kernel panic.  This was reported [1] when running mm/ksft_hmm.sh on arm64,
where a test failure triggered SIGABRT and the resulting coredump walked
the VMAs faulting in the stale device private pages.

Fix this by calling dmirror_device_evict_chunk() for each devmem chunk in
dmirror_fops_release() to migrate all device private pages back to system
memory before freeing the dmirror struct.  The function is moved earlier
in the file to avoid a forward declaration.

Link: https://lore.kernel.org/20260331063445.3551404-1-apopple@nvidia.com
Link: https://lore.kernel.org/20260331063445.3551404-2-apopple@nvidia.com
Fixes: b2ef9f5a5cb3 ("mm/hmm/test: add selftest driver for HMM")
Signed-off-by: Alistair Popple 
Reported-by: Zenghui Yu 
Closes: https://lore.kernel.org/linux-mm/8bd0396a-8997-4d2e-a13f-5aac033083d7@linux.dev/
Reviewed-by: Balbir Singh 
Tested-by: Zenghui Yu 
Cc: David Hildenbrand 
Cc: Jason Gunthorpe 
Cc: Leon Romanovsky 
Cc: Liam Howlett 
Cc: Lorenzo Stoakes (Oracle) 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Suren Baghdasaryan 
Cc: Zenghui Yu 
Cc: Matthew Brost 
Cc: 
Signed-off-by: Andrew Morton 
[ kept the existing simpler `dmirror_device_evict_chunk()` body instead of the upstream compound-folio version ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mm/alloc_tag: clear codetag for pages allocated before page_ext initialization

2026-05-07T04:11:39+00:00

commit 6b1842775a460245e97d36d3a67d0cfba7c4ff79 upstream.

Due to initialization ordering, page_ext is allocated and initialized
relatively late during boot.  Some pages have already been allocated and
freed before page_ext becomes available, leaving their codetag
uninitialized.

A clear example is in init_section_page_ext(): alloc_page_ext() calls
kmemleak_alloc().  If the slab cache has no free objects, it falls back to
the buddy allocator to allocate memory.  However, at this point page_ext
is not yet fully initialized, so these newly allocated pages have no
codetag set.  These pages may later be reclaimed by KASAN, which causes
the warning to trigger when they are freed because their codetag ref is
still empty.

Use a global array to track pages allocated before page_ext is fully
initialized.  The array size is fixed at 8192 entries, and will emit a
warning if this limit is exceeded.  When page_ext initialization
completes, set their codetag to empty to avoid warnings when they are
freed later.

This warning is only observed with CONFIG_MEM_ALLOC_PROFILING_DEBUG=Y and
mem_profiling_compressed disabled:

[    9.582133] ------------[ cut here ]------------
[    9.582137] alloc_tag was not set
[    9.582139] WARNING: ./include/linux/alloc_tag.h:164 at __pgalloc_tag_sub+0x40f/0x550, CPU#5: systemd/1
[    9.582190] CPU: 5 UID: 0 PID: 1 Comm: systemd Not tainted 7.0.0-rc4 #1 PREEMPT(lazy)
[    9.582192] Hardware name: Red Hat KVM, BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[    9.582194] RIP: 0010:__pgalloc_tag_sub+0x40f/0x550
[    9.582196] Code: 00 00 4c 29 e5 48 8b 05 1f 88 56 05 48 8d 4c ad 00 48 8d 2c c8 e9 87 fd ff ff 0f 0b 0f 0b e9 f3 fe ff ff 48 8d 3d 61 2f ed 03 <67> 48 0f b9 3a e9 b3 fd ff ff 0f 0b eb e4 e8 5e cd 14 02 4c 89 c7
[    9.582197] RSP: 0018:ffffc9000001f940 EFLAGS: 00010246
[    9.582200] RAX: dffffc0000000000 RBX: 1ffff92000003f2b RCX: 1ffff110200d806c
[    9.582201] RDX: ffff8881006c0360 RSI: 0000000000000004 RDI: ffffffff9bc7b460
[    9.582202] RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff3a62324
[    9.582203] R10: ffffffff9d311923 R11: 0000000000000000 R12: ffffea0004001b00
[    9.582204] R13: 0000000000002000 R14: ffffea0000000000 R15: ffff8881006c0360
[    9.582206] FS:  00007ffbbcf2d940(0000) GS:ffff888450479000(0000) knlGS:0000000000000000
[    9.582208] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    9.582210] CR2: 000055ee3aa260d0 CR3: 0000000148b67005 CR4: 0000000000770ef0
[    9.582211] PKRU: 55555554
[    9.582212] Call Trace:
[    9.582213]  
[    9.582214]  ? __pfx___pgalloc_tag_sub+0x10/0x10
[    9.582216]  ? check_bytes_and_report+0x68/0x140
[    9.582219]  __free_frozen_pages+0x2e4/0x1150
[    9.582221]  ? __free_slab+0xc2/0x2b0
[    9.582224]  qlist_free_all+0x4c/0xf0
[    9.582227]  kasan_quarantine_reduce+0x15d/0x180
[    9.582229]  __kasan_slab_alloc+0x69/0x90
[    9.582232]  kmem_cache_alloc_noprof+0x14a/0x500
[    9.582234]  do_getname+0x96/0x310
[    9.582237]  do_readlinkat+0x91/0x2f0
[    9.582239]  ? __pfx_do_readlinkat+0x10/0x10
[    9.582240]  ? get_random_bytes_user+0x1df/0x2c0
[    9.582244]  __x64_sys_readlinkat+0x96/0x100
[    9.582246]  do_syscall_64+0xce/0x650
[    9.582250]  ? __x64_sys_getrandom+0x13a/0x1e0
[    9.582252]  ? __pfx___x64_sys_getrandom+0x10/0x10
[    9.582254]  ? do_syscall_64+0x114/0x650
[    9.582255]  ? ksys_read+0xfc/0x1d0
[    9.582258]  ? __pfx_ksys_read+0x10/0x10
[    9.582260]  ? do_syscall_64+0x114/0x650
[    9.582262]  ? do_syscall_64+0x114/0x650
[    9.582264]  ? __pfx_fput_close_sync+0x10/0x10
[    9.582266]  ? file_close_fd_locked+0x178/0x2a0
[    9.582268]  ? __x64_sys_faccessat2+0x96/0x100
[    9.582269]  ? __x64_sys_close+0x7d/0xd0
[    9.582271]  ? do_syscall_64+0x114/0x650
[    9.582273]  ? do_syscall_64+0x114/0x650
[    9.582275]  ? clear_bhb_loop+0x50/0xa0
[    9.582277]  ? clear_bhb_loop+0x50/0xa0
[    9.582279]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[    9.582280] RIP: 0033:0x7ffbbda345ee
[    9.582282] Code: 0f 1f 40 00 48 8b 15 29 38 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 0f 1f 40 00 f3 0f 1e fa 49 89 ca b8 0b 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d fa 37 0d 00 f7 d8 64 89 01 48
[    9.582284] RSP: 002b:00007ffe2ad8de58 EFLAGS: 00000202 ORIG_RAX: 000000000000010b
[    9.582286] RAX: ffffffffffffffda RBX: 000055ee3aa25570 RCX: 00007ffbbda345ee
[    9.582287] RDX: 000055ee3aa25570 RSI: 00007ffe2ad8dee0 RDI: 00000000ffffff9c
[    9.582288] RBP: 0000000000001000 R08: 0000000000000003 R09: 0000000000001001
[    9.582289] R10: 0000000000001000 R11: 0000000000000202 R12: 0000000000000033
[    9.582290] R13: 00007ffe2ad8dee0 R14: 00000000ffffff9c R15: 00007ffe2ad8deb0
[    9.582292]  
[    9.582293] ---[ end trace 0000000000000000 ]---

Link: https://lore.kernel.org/20260331081312.123719-1-hao.ge@linux.dev
Fixes: dcfe378c81f72 ("lib: introduce support for page allocation tagging")
Signed-off-by: Hao Ge 
Suggested-by: Suren Baghdasaryan 
Acked-by: Suren Baghdasaryan 
Cc: Kent Overstreet 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

lib/ts_kmp: fix integer overflow in pattern length calculation

2026-05-07T04:11:37+00:00

commit 8cdf30813ea8ce881cecc08664144416dbdb3e16 upstream.

The ts_kmp algorithm stores its prefix_tbl[] table and pattern in a single
allocation sized from the pattern length.  If the prefix_tbl[] size
calculation wraps, the resulting allocation can be too small and
subsequent pattern copies can overflow it.

Fix this by rejecting zero-length patterns and by using overflow helpers
before calculating the combined allocation size.


This fixes a potential heap overflow.  The pattern length calculation can
wrap during a size_t addition, leading to an undersized allocation.
Because the textsearch library is reachable from userspace via Netfilter's
xt_string module, this is a security risk that should be backported to LTS
kernels.

Link: https://lkml.kernel.org/r/20260308202028.2889285-2-objecting@objecting.org
Signed-off-by: Josh Law 
Reviewed-by: Andrew Morton 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

lib/crypto: tests: Drop the default to CRYPTO_SELFTESTS

2026-04-27T13:27:29+00:00

commit 6d80749becf8fc5ffa004194e578f79b558235ef upstream.

Defaulting the crypto KUnit tests to KUNIT_ALL_TESTS || CRYPTO_SELFTESTS
instead of simply KUNIT_ALL_TESTS was originally intended to make it
easy to enable all the crypto KUnit tests.  This additional default is
nonstandard for KUnit tests, though, and it can cause all the KUnit
tests to be built-in unexpectedly if CRYPTO_SELFTESTS is set.  It also
constitutes a back-reference to crypto/ from lib/crypto/, which is
something that we should be avoiding in order to get clean layering.

Now that we provide a lib/crypto/.kunitconfig file that enables all
crypto KUnit tests, let's consider that to be the supported way to
enable all these tests, and drop the default of CRYPTO_SELFTESTS.

Acked-by: Ard Biesheuvel 
Link: https://lore.kernel.org/r/20260317040626.5697-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

lib/crypto: tests: Introduce CRYPTO_LIB_ENABLE_ALL_FOR_KUNIT

2026-04-27T13:27:29+00:00

commit ed1767442d919f57aaf83d69c33853da2644d902 upstream.

For kunit.py to run all the crypto library tests when passed the
--alltests option, tools/testing/kunit/configs/all_tests.config needs to
enable options that satisfy the test dependencies.

This is the same as what lib/crypto/.kunitconfig already does.
However, the strategy that lib/crypto/.kunitconfig currently uses to
select all the hidden library options isn't going to scale up well when
it needs to be repeated in two places.

Instead let's go ahead and introduce an option
CRYPTO_LIB_ENABLE_ALL_FOR_KUNIT that depends on KUNIT and selects all
the crypto library options that have corresponding KUnit tests.

Update lib/crypto/.kunitconfig to use this option.

Link: https://lore.kernel.org/r/20260314035927.51351-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

lib/crypto: tests: Add a .kunitconfig file

2026-04-27T13:27:29+00:00

commit 20d6f07004d639967dcb00994d56ce6d16118e9e upstream.

Add a .kunitconfig file to the lib/crypto/ directory so that the crypto
library tests can be run more easily using kunit.py.  Example with UML:

    tools/testing/kunit/kunit.py run --kunitconfig=lib/crypto

Example with QEMU:

    tools/testing/kunit/kunit.py run --kunitconfig=lib/crypto --arch=arm64 --make_options LLVM=1

Acked-by: Ard Biesheuvel 
Link: https://lore.kernel.org/r/20260301040140.490310-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

lib/crc: tests: Add a .kunitconfig file

2026-04-27T13:27:29+00:00

commit c13cee2fc7f137dd25ed50c63eddcc578624f204 upstream.

Add a .kunitconfig file to the lib/crc/ directory so that the CRC
library tests can be run more easily using kunit.py.  Example with UML:

    tools/testing/kunit/kunit.py run --kunitconfig=lib/crc

Example with QEMU:

    tools/testing/kunit/kunit.py run --kunitconfig=lib/crc --arch=arm64 --make_options LLVM=1

Link: https://lore.kernel.org/r/20260306033557.250499-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

lib/crc: tests: Add CRC_ENABLE_ALL_FOR_KUNIT

2026-04-27T13:27:29+00:00

commit cdf22aeaad8430905c3aa3b3d0f2686c65395c22 upstream.

Now that crc_kunit uses the standard "depends on" pattern, enabling the
full set of CRC tests is a bit difficult, mainly due to CRC7 being
rarely used.  Add a kconfig option to make it easier.  It is visible
only when KUNIT, so hopefully the extra prompt won't be too annoying.

Link: https://lore.kernel.org/r/20260306033557.250499-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

lib/crc: tests: Make crc_kunit test only the enabled CRC variants

2026-04-27T13:27:29+00:00

commit 85c9f3a2b805eb96d899da7bcc38a16459aa3c16 upstream.

Like commit 4478e8eeb871 ("lib/crypto: tests: Depend on library options
rather than selecting them") did with the crypto library tests, make
crc_kunit depend on the code it tests rather than selecting it.  This
follows the standard convention for KUnit and fixes an issue where
enabling KUNIT_ALL_TESTS enabled non-test code.

crc_kunit does differ from the crypto library tests in that it
consolidates the tests for multiple CRC variants, with 5 kconfig
options, into one KUnit suite.  Since depending on *all* of these
kconfig options would greatly restrict the ability to enable crc_kunit,
instead just depend on *any* of these options.  Update crc_kunit
accordingly to test only the reachable code.

Alternatively we could split crc_kunit into 5 test suites.  But keeping
it as one is simpler for now.

Fixes: e47d9b1a76ed ("lib/crc_kunit.c: add KUnit test suite for CRC library functions")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20260306033557.250499-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

x86-64/arm64/powerpc: clean up and rename __copy_from_user_flushcache

2026-04-22T11:22:31+00:00

commit 809b997a5ce945ab470f70c187048fe4f5df20bf upstream.

This finishes the work on these odd functions that were only implemented
by a handful of architectures.

The 'flushcache' function was only used from the iterator code, and
let's make it do the same thing that the nontemporal version does:
remove the two underscores and add the user address checking.

Yes, yes, the user address checking is also done at iovec import time,
but we have long since walked away from the old double-underscore thing
where we try to avoid address checking overhead at access time, and
these functions shouldn't be so special and old-fashioned.

The arm64 version already did the address check, in fact, so there it's
just a matter of renaming it.  For powerpc and x86-64 we now do the
proper user access boilerplate.

Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman