CVE-2025-40327 (GCVE-0-2025-40327)

Vulnerability from cvelistv5 – Published: 2025-12-09 04:09 – Updated: 2026-05-23 16:02
VLAI
Title
perf/core: Fix system hang caused by cpu-clock usage
Summary
In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix system hang caused by cpu-clock usage cpu-clock usage by the async-profiler tool can trigger a system hang, which got bisected back to the following commit by Octavia Togami: 18dbcbfabfff ("perf: Fix the POLL_HUP delivery breakage") causes this issue The root cause of the hang is that cpu-clock is a special type of SW event which relies on hrtimers. The __perf_event_overflow() callback is invoked from the hrtimer handler for cpu-clock events, and __perf_event_overflow() tries to call cpu_clock_event_stop() to stop the event, which calls htimer_cancel() to cancel the hrtimer. But that's a recursion into the hrtimer code from a hrtimer handler, which (unsurprisingly) deadlocks. To fix this bug, use hrtimer_try_to_cancel() instead, and set the PERF_HES_STOPPED flag, which causes perf_swevent_hrtimer() to stop the event once it sees the PERF_HES_STOPPED flag. [ mingo: Fixed the comments and improved the changelog. ]
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 18dbcbfabfffc4a5d3ea10290c5ad27f22b0d240 , < 6b8c512811644cf2f5eaf6f44e928683c54127f0 (git)
Affected: 18dbcbfabfffc4a5d3ea10290c5ad27f22b0d240 , < eb3182ef0405ff2f6668fd3e5ff9883f60ce8801 (git)
Affected: b2de0c9ce8e542b5cb4cd3944620d9dd1ea1f0ac (git)
Affected: 6.16.8 , < 6.17 (semver)
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Linux Linux Affected: 6.17
Unaffected: 0 , < 6.17 (semver)
Unaffected: 6.17.8 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)
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{
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          }
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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