{"id":"CVE-2025-40327","summary":"perf/core: Fix system hang caused by cpu-clock usage","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Fix system hang caused by cpu-clock usage\n\ncpu-clock usage by the async-profiler tool can trigger a system hang,\nwhich got bisected back to the following commit by Octavia Togami:\n\n  18dbcbfabfff (\"perf: Fix the POLL_HUP delivery breakage\") causes this issue\n\nThe root cause of the hang is that cpu-clock is a special type of SW\nevent which relies on hrtimers. The __perf_event_overflow() callback\nis invoked from the hrtimer handler for cpu-clock events, and\n__perf_event_overflow() tries to call cpu_clock_event_stop()\nto stop the event, which calls htimer_cancel() to cancel the hrtimer.\n\nBut that's a recursion into the hrtimer code from a hrtimer handler,\nwhich (unsurprisingly) deadlocks.\n\nTo fix this bug, use hrtimer_try_to_cancel() instead, and set\nthe PERF_HES_STOPPED flag, which causes perf_swevent_hrtimer()\nto stop the event once it sees the PERF_HES_STOPPED flag.\n\n[ mingo: Fixed the comments and improved the changelog. ]","modified":"2026-04-02T12:48:22.483158Z","published":"2025-12-09T04:09:43.522Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40327.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/6b8c512811644cf2f5eaf6f44e928683c54127f0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/eb3182ef0405ff2f6668fd3e5ff9883f60ce8801"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40327.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-40327"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"18dbcbfabfffc4a5d3ea10290c5ad27f22b0d240"},{"fixed":"6b8c512811644cf2f5eaf6f44e928683c54127f0"},{"fixed":"eb3182ef0405ff2f6668fd3e5ff9883f60ce8801"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"b2de0c9ce8e542b5cb4cd3944620d9dd1ea1f0ac"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40327.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.17.0"},{"fixed":"6.17.8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40327.json"}}],"schema_version":"1.7.5"}