Bug 2365244 (CVE-2025-37880)

Summary: CVE-2025-37880 kernel: um: work around sched_yield not yielding in time-travel mode
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: low    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-05-09 07:01:21 UTC 
In the Linux kernel, the following vulnerability has been resolved:

um: work around sched_yield not yielding in time-travel mode

sched_yield by a userspace may not actually cause scheduling in
time-travel mode as no time has passed. In the case seen it appears to
be a badly implemented userspace spinlock in ASAN. Unfortunately, with
time-travel it causes an extreme slowdown or even deadlock depending on
the kernel configuration (CONFIG_UML_MAX_USERSPACE_ITERATIONS).

Work around it by accounting time to the process whenever it executes a
sched_yield syscall.
Comment 1 Michal Findra 2025-05-09 09:46:57 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025050943-CVE-2025-37880-3f3c@gregkh/T