# CVE-2022-49782: perf: Improve missing SIGTRAP checking

Status: published. Published: 2025-05-01. Updated: 2026-11-05.

In the Linux kernel, the following vulnerability has been resolved:

perf: Improve missing SIGTRAP checking

To catch missing SIGTRAP we employ a WARN in __perf_event_overflow(),
which fires if pending_sigtrap was already set: returning to user space
without consuming pending_sigtrap, and then having the event fire again
would re-enter the kernel and trigger the WARN.

This, however, seemed to miss the case where some events not associated
with progress in the user space task can fire and the interrupt handler
runs before the IRQ work meant to consume pending_sigtrap (and generate
the SIGTRAP).

syzbot gifted us this stack trace:

 | WARNING: CPU: 0 PID: 3607 at kernel/events/core.c:9313 __perf_event_overflow
 | Modules linked in:
 | CPU: 0 PID: 3607 Comm: syz-executor100 Not tainted 6.1.0-rc2-syzkaller-00073-g88619e77b33d #0
 | Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
 | RIP: 0010:__perf_event_overflow+0x498/0x540 kernel/events/core.c:9313
 | <...>
 | Call Trace:
 |  <TASK>
 |  perf_swevent_hrtimer+0x34f/0x3c0 kernel/events/core.c:10729
 |  __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 |  __hrtimer_run_queues+0x1c6/0xfb0 kernel/time/hrtimer.c:1749
 |  hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811
 |  local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1096 [inline]
 |  __sysvec_apic_timer_interrupt+0x17c/0x640 arch/x86/kernel/apic/apic.c:1113
 |  sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1107
 |  asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
 | <...>
 |  </TASK>

In this case, syzbot produced a program with event type
PERF_TYPE_SOFTWARE and config PERF_COUNT_SW_CPU_CLOCK. The hrtimer
manages to fire again before the IRQ work got a chance to run, all while
never having returned to user space.

Improve the WARN to check for real progress in user space: approximate
this by storing a 32-bit hash of the current IP into pending_sigtrap,
and if an event fires while pending_sigtrap still matches the previous
IP, we assume no progress (false negatives are possible given we could
return to user space and trigger again on the same IP).

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ ca7b0a10287e2733bdafb01ef0d4038536625fe3; < 35c60b4e8ca76712dd03bafe2598e31578248916 (affected, git); ≥ 078c12ccf1fb943cc18c84894c76113dc89e5975; < b09221f1b4944d2866d06ac35e59d7a6f8916c9f (affected, git); ≥ ca6c21327c6af02b7eec31ce4b9a740a18c6c13f; < bb88f9695460bec25aa30ba9072595025cf6c8af (affected, git). Source: CNA: Linux
- Linux / Linux: ≥ 5.15.77; < 5.15.80 (affected, semver); ≥ 6.0.7; < 6.0.10 (affected, semver). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.20% as of 2026-11-05; percentile 9.81%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/35c60b4e8ca76712dd03bafe2598e31578248916 (CNA: Linux)

- https://git.kernel.org/stable/c/b09221f1b4944d2866d06ac35e59d7a6f8916c9f (CNA: Linux)

- https://git.kernel.org/stable/c/bb88f9695460bec25aa30ba9072595025cf6c8af (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2022-49782; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2022-49782; retrieved 2026-11-05; source updated Not reported

Revision: 680a7233da5d229bf7cc08966fbc5f23c971b506f445e1ab3d5b56142c0a91e4

Canonical: https://y2.dev/cve/CVE-2022-49782

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