x86/alternatives: Exclude text poking against change_page_attr()
Summary
| CVE | CVE-2026-97942 |
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| State | PUBLISHED |
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| Assigner | Linux |
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| Source Priority | CVE Program / NVD first with legacy fallback |
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| Published | 2026-09-25 11:17:21 UTC |
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| Updated | 2026-09-25 11:17:21 UTC |
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| Description | In the Linux kernel, the following vulnerability has been resolved:
x86/alternatives: Exclude text poking against change_page_attr()
From time to time, the following BUG can be observed
in the x86 alternatives patching code [0]:
> kernel BUG at arch/x86/kernel/alternative.c:2576!
> Oops: invalid opcode: 0000 [#1] SMP NOPTI
> CPU: 0 UID: 0 PID: 355 Comm: (udev-worker) Not tainted 7.1.3-1-default #1 PREEMPT(full) openSUSE Tumbleweed 8c1795b03ec64f997e57a8ad38b1161e3b98da64
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS unknown 02/02/2022
> RIP: 0010:__text_poke+0x2aa/0x450
> Call Trace:
> <TASK>
> smp_text_poke_batch_finish+0x2a7/0x320
> __static_call_transform+0xb7/0x220
> arch_static_call_transform+0x5b/0xb0
> __static_call_init+0xe9/0x270
> static_call_module_notify+0x11f/0x150
> notifier_call_chain+0x61/0xe0
> blocking_notifier_call_chain_robust+0x63/0xc0
> load_module+0x1c92/0x20c0
> init_module_from_file+0xd8/0x140
> idempotent_init_module+0x100/0x2f0
> __x64_sys_finit_module+0x71/0xe0
> do_syscall_64+0xe1/0x610
> entry_SYSCALL_64_after_hwframe+0x76/0x7e
which matches the following BUG_ON() in alternative.c:
/*
* If something went wrong, crash and burn since recovery paths are not
* implemented.
*/
BUG_ON(!pages[0] || (cross_page_boundary && !pages[1]));
This can happen if vmalloc_to_page() fails, for any reason. Such can happen
if text poking races with CPA, which can possibly result in the collapsing
of page tables (or breaking of PMD hugepages). It is not a problem for most
users of vmalloc_to_page() (they solely own the vmalloc'd range) but, when
CONFIG_ARCH_HAS_EXECMEM_ROX=y, various modules own a single execmem vmalloc
range, and can call set_memory_*() in parallel on it. This can happen to
race against __text_poke and cause havoc in vmalloc_to_page().
Fix it by excluding against CPA using the init_mm mmap read lock.
[ dhansen: Fix up SoB ordering. The actual code flow here was:
Pedro=>Lorenzo=>Mike=>Me which is reflected in the SoB chain
now. I *believe* Mike simply picked up Lorenzo's update to
Pedro's post from the Link ] |
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Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|
| CNA |
Linux |
Linux |
affected 64f6a4e10c05ed527f0f24b7954964255e0d3535 281e6f536f2f3f95d91938c5bd7ba9bcb4c1049d git |
Not specified |
| CNA |
Linux |
Linux |
affected 64f6a4e10c05ed527f0f24b7954964255e0d3535 89c60435b90d32ab5e3a39da3ae73d463d07debe git |
Not specified |
| CNA |
Linux |
Linux |
affected 64f6a4e10c05ed527f0f24b7954964255e0d3535 1587d3394e254639cc36516256031334095e6ef3 git |
Not specified |
| CNA |
Linux |
Linux |
affected 6.15 |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.15 semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.18.53 6.18.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.2.7 7.2.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.3-rc4 * original_commit_for_fix |
Not specified |
References
| Reference | Source | Link | Tags |
|---|
| git.kernel.org/stable/c/1587d3394e254639cc36516256031334095e6ef3 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/89c60435b90d32ab5e3a39da3ae73d463d07debe |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/281e6f536f2f3f95d91938c5bd7ba9bcb4c1049d |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| CVE Program record |
CVE.ORG |
www.cve.org |
canonical |
| NVD vulnerability detail |
NVD |
nvd.nist.gov |
canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.