mm: memcg: stop reclaim when a limit update is superseded
Summary
| CVE | CVE-2026-89752 |
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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 | 2026-09-11 20:20:06 UTC |
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| Updated | 2026-09-11 20:20:06 UTC |
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| Description | In the Linux kernel, the following vulnerability has been resolved:
mm: memcg: stop reclaim when a limit update is superseded
kernfs serializes file operations only per open file, so separate open
files can update the same memory.high or memory.max file concurrently.
Both handlers store the new limit before synchronous reclaim, but continue
to use the writer's local target in the reclaim loop. If another writer
raises or removes the limit, the first writer can continue reclaiming
toward a stale target.
For memory.max, this can leave the writer looping indefinitely once
reclaim retries are exhausted. The OOM path sees sufficient margin under
the current limit and returns true without killing, while the writer still
compares usage against its stale target and records another OOM event.
Check the current limit at the start of each reclaim iteration and stop if
it no longer matches the writer's target.
Reproducer:
Populate a cgroup with anonymous memory and disable swapping. Lower
memory.max from one open file, then restore it to "max" through another
open file after the new limit becomes visible.
Without the patch, the first writer remains blocked and repeatedly
increments the OOM event counter. With the patch, it returns normally.
This was not motivated by a reported production workload. We found it
through automated randomized testing for our cgroup observability work
and reduced it to the reproducer above. |
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Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|
| CNA |
Linux |
Linux |
affected b6e6edcfa40561e9c8abe5eecf1c96f8e5fd9c6f 39ec1e4183a718f448b2e9de681dcbdda18fce42 git |
Not specified |
| CNA |
Linux |
Linux |
affected b6e6edcfa40561e9c8abe5eecf1c96f8e5fd9c6f 95d87030cae7764805aa7c621c52871139297cb0 git |
Not specified |
| CNA |
Linux |
Linux |
affected b6e6edcfa40561e9c8abe5eecf1c96f8e5fd9c6f aab391074de96ed601eeca32daef9a8507d436d9 git |
Not specified |
| CNA |
Linux |
Linux |
affected b6e6edcfa40561e9c8abe5eecf1c96f8e5fd9c6f 9477820c63cbf4d97114238f3d1ff10dfd6bee3f git |
Not specified |
| CNA |
Linux |
Linux |
affected 0ccab5b139971a2a3f48df24d1ee8be2dbf84042 git |
Not specified |
| CNA |
Linux |
Linux |
affected 97729c37439040ec07807f0dbb71ea60ccbafd27 git |
Not specified |
| CNA |
Linux |
Linux |
affected 4.4.7 4.5 semver |
Not specified |
| CNA |
Linux |
Linux |
affected 4.5.1 4.6 semver |
Not specified |
| CNA |
Linux |
Linux |
affected 4.6 |
Not specified |
| CNA |
Linux |
Linux |
unaffected 4.6 semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.12.109 6.12.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.18.50 6.18.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.2.4 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/9477820c63cbf4d97114238f3d1ff10dfd6bee3f |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/aab391074de96ed601eeca32daef9a8507d436d9 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/39ec1e4183a718f448b2e9de681dcbdda18fce42 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/95d87030cae7764805aa7c621c52871139297cb0 |
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.