Bug 2337128 (CVE-2024-41932)

Summary: CVE-2024-41932 kernel: sched: fix warning in sched_setaffinity
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-01-11 13:03:29 UTC 
In the Linux kernel, the following vulnerability has been resolved:

sched: fix warning in sched_setaffinity

Commit 8f9ea86fdf99b added some logic to sched_setaffinity that included
a WARN when a per-task affinity assignment races with a cpuset update.

Specifically, we can have a race where a cpuset update results in the
task affinity no longer being a subset of the cpuset. That's fine; we
have a fallback to instead use the cpuset mask. However, we have a WARN
set up that will trigger if the cpuset mask has no overlap at all with
the requested task affinity. This shouldn't be a warning condition; its
trivial to create this condition.

Reproduced the warning by the following setup:

- $PID inside a cpuset cgroup
- another thread repeatedly switching the cpuset cpus from 1-2 to just 1
- another thread repeatedly setting the $PID affinity (via taskset) to 2
Comment 1 Avinash Hanwate 2025-01-13 06:23:03 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025011116-CVE-2024-41932-ed84@gregkh/T