perf: Fix hang while freeing sigtrap event
Summary
perf: Fix hang while freeing sigtrap event
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
perf: Fix hang while freeing sigtrap event
Perf can hang while freeing a sigtrap event if a related deferred
signal hadn't managed to be sent before the file got closed:
perf_event_overflow()
task_work_add(perf_pending_task)
fput()
task_work_add(____fput())
task_work_run()
____fput()
perf_release()
perf_event_release_kernel()
_free_event()
perf_pending_task_sync()
task_work_cancel() -> FAILED
rcuwait_wait_event()
Once task_work_run() is running, the list of pending callbacks is
removed from the task_struct and from this point on task_work_cancel()
can't remove any pending and not yet started work items, hence the
task_work_cancel() failure and the hang on rcuwait_wait_event().
Task work could be changed to remove one work at a time, so a work
running on the current task can always cancel a pending one, however
the wait / wake design is still subject to inverted dependencies when
remote targets are involved, as pictured by Oleg:
T1 T2
fd = perf_event_open(pid => T2->pid); fd = perf_event_open(pid => T1->pid);
close(fd) close(fd)
perf_event_overflow() perf_event_overflow()
task_wo…
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2025-37747 linux-lts
- Debian DEBIAN-CVE-2025-37747 linux
- Ubuntu UBUNTU-CVE-2025-37747 linux-hwe-edge
References
- advisory github.com
- advisory nvd.nist.gov
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org