mm: memcg: stop reclaim when a limit update is superseded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.
Metrics
Affected Vendors & Products
No data.
No data.
OpenCVE Enrichment is a feature of OpenCVE that uses AI to automatically link vendors and products to CVEs. Learn more on GitHub.
No data.
No advisories yet.
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Sat, 12 Sep 2026 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-367 | |
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Fri, 11 Sep 2026 23:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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| In the Linux kernel, the following vulnerability has been resolved: mm: memcg: stop reclaim when a limit update is superseded kernfs serializes file operations only per open file, so separate open files can update the same memory.high or memory.max file concurrently.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. | |
| Title | mm: memcg: stop reclaim when a limit update is superseded | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
Sign in to view the affected projects.
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-11T19:46:56.059Z
Reserved: 2026-09-11T19:38:34.763Z
Link: CVE-2026-89752
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-11T20:20:06.123
Modified: 2026-09-11T20:20:06.123
Link: CVE-2026-89752
Redhat
OpenCVE Enrichment
Updated: 2026-09-12T12:15:13Z