kcov: fix data corruption and race conditions on PREEMPT_RT
Summary
| CVE | CVE-2026-80916 |
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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 | 2026-09-09 17:17:46 UTC |
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| Updated | 2026-09-09 17:17:46 UTC |
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| Description | In the Linux kernel, the following vulnerability has been resolved:
kcov: fix data corruption and race conditions on PREEMPT_RT
syzbot is reporting KCOV state corruption on PREEMPT_RT kernels, for the
temporary storage used for saving/restoring remote KCOV state is currently
allocated as the per-CPU area.
On PREEMPT_RT kernels, softirq handlers run as preemptible task threads
(e.g., ksoftirqd). If a softirq context preempts a task running a remote
KCOV session, it safely saves the task's state into the per-CPU area.
However, if that softirq thread is subsequently preempted by a higher-
priority softirq thread on the same CPU, the second softirq will overwrite
the same per-CPU area, permanently destroying the original task's KCOV
state.
Fix this data corruption by moving the temporary storage from the per-CPU
area to the per-thread area. Since each softirq thread now owns its own
task context, nested softirq preemption no longer causes data overwrites.
Note that while the temporary storage is now on a per-thread basis, the
per-CPU kcov_percpu_data.lock must be retained, for we need to ensure that
kcov_remote_start() and kcov_remote_stop() operate atomically without
racing against asynchronous interrupts that manipulate the current task's
KCOV state.
It is likely that GFP_KERNEL allocation by vmalloc_node() in kcov_init()
has already called panic() before returning NULL, for there will be no
OOM-killable userspace processes when __init function of built-in module
runs. But this patch also fixes crashing the kernel when vmalloc_node()
in kcov_init() returned NULL, for kcov_init() left per-CPU irq_area == NULL
but kcov_remote_start() depends on per-CPU irq_area != NULL, resulting in
(1) doing vmalloc() in kcov_remote_start() despite !in_task() context
(2) out-of-array-bounds access if (1) succeeded but
kcov->remote_size < CONFIG_KCOV_IRQ_AREA_SIZE
(3) always leak memory allocated by (1), eventually killing all
OOM-killable userspace processes
problems. |
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Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|
| CNA |
Linux |
Linux |
affected 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 ef7048d8a614c5f5a9b20513a5428101a744514e git |
Not specified |
| CNA |
Linux |
Linux |
affected 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 8ed3ddf23d39bf5338406bd9f8863d44748cf6ce git |
Not specified |
| CNA |
Linux |
Linux |
affected 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 5dc59fc959b2b5742985d7ef24bccd1868217dc2 git |
Not specified |
| CNA |
Linux |
Linux |
affected 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 a2fb8222cde23b0001812ed3acb7c0ea36dd94e2 git |
Not specified |
| CNA |
Linux |
Linux |
affected 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 18799e858b407bf355383c9dd6c06477aa437134 git |
Not specified |
| CNA |
Linux |
Linux |
affected 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 e11f5b48c82703242a3be7a7ae4b4940b4cb4610 git |
Not specified |
| CNA |
Linux |
Linux |
affected 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 22670d1552fe155822b2abf91f920925f7d067b4 git |
Not specified |
| CNA |
Linux |
Linux |
affected 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 f8c9a3ec36b4ee3d4701b9be08f40e7bfbf89761 git |
Not specified |
| CNA |
Linux |
Linux |
affected 5ff3b30ab57da82d8db4f14662a2858cabfbc2c0 2eed77fdcb0cc48e8eccb2bcd4b7f2c6d650e84c git |
Not specified |
| CNA |
Linux |
Linux |
affected 5.8 |
Not specified |
| CNA |
Linux |
Linux |
unaffected 5.8 semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 5.10.269 5.10.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 5.15.220 5.15.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.1.185 6.1.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.6.154 6.6.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.12.106 6.12.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.18.47 6.18.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.1.11 7.1.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.2.1 7.2.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.3-rc1 * original_commit_for_fix |
Not specified |
References
| Reference | Source | Link | Tags |
|---|
| git.kernel.org/stable/c/a2fb8222cde23b0001812ed3acb7c0ea36dd94e2 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/f8c9a3ec36b4ee3d4701b9be08f40e7bfbf89761 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/5dc59fc959b2b5742985d7ef24bccd1868217dc2 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/18799e858b407bf355383c9dd6c06477aa437134 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/e11f5b48c82703242a3be7a7ae4b4940b4cb4610 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/22670d1552fe155822b2abf91f920925f7d067b4 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/ef7048d8a614c5f5a9b20513a5428101a744514e |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/2eed77fdcb0cc48e8eccb2bcd4b7f2c6d650e84c |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/8ed3ddf23d39bf5338406bd9f8863d44748cf6ce |
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.