Description
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. ]
Product status
18dbcbfabfffc4a5d3ea10290c5ad27f22b0d240 (git) before 6b8c512811644cf2f5eaf6f44e928683c54127f0
18dbcbfabfffc4a5d3ea10290c5ad27f22b0d240 (git) before eb3182ef0405ff2f6668fd3e5ff9883f60ce8801
b2de0c9ce8e542b5cb4cd3944620d9dd1ea1f0ac (git)
6.17
Any version before 6.17
6.17.8 (semver)
6.18 (original_commit_for_fix)
References
git.kernel.org/...c/6b8c512811644cf2f5eaf6f44e928683c54127f0
git.kernel.org/...c/eb3182ef0405ff2f6668fd3e5ff9883f60ce8801
