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CVE PROGRAM SOURCE RECORDUnscored

CVE-2024-43870

perf: Fix event leak upon exit

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: perf: Fix event leak upon exit When a task is scheduled out, pending sigtrap deliveries are deferred to the target task upon resume to userspace via task_work. However failures while adding an event's callback to the task_work engine are ignored. And since the last call for events exit happen after task work is eventually closed, there is a small window during which pending sigtrap can be queued though ignored, leaking the event refcount addition such as in the following scenario: TASK A ----- do_exit() exit_task_work(tsk); <IRQ> perf_event_overflow() event->pending_sigtrap = pending_id; irq_work_queue(&event->pending_irq); </IRQ> =========> PREEMPTION: TASK A -> TASK B event_sched_out() event->pending_sigtrap = 0; atomic_long_inc_not_zero(&event->refcount) // FAILS: task work has exited task_work_add(&event->pending_task) [...] <IRQ WORK> perf_pending_irq() // early return: event->oncpu = -1 </IRQ WORK> [...] =========> TASK B -> TASK A perf_event_exit_task(tsk) perf_event_exit_event() free_event() WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1) // leak event due to unexpected refcount == 2 As a result the event is never released while the task exits. Fix this with appropriate task_work_add()'s error handling.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 8bffa95ac19ff27c8261904f89d36c7fcf215d59 to < 67fad724f1b568b356c1065d50df46e6b30eb2f7affected
  • 517e6a301f34613bff24a8e35b5455884f2d83d8 to < 70882d7fa74f0731492a0d493e8515a4f7131831affected
  • 517e6a301f34613bff24a8e35b5455884f2d83d8 to < 05d3fd599594abf79aad4484bccb2b26e1cb0b51affected
  • 517e6a301f34613bff24a8e35b5455884f2d83d8 to < 3d7a63352a93bdb8a1cdf29606bf617d3ac1c22aaffected
  • 517e6a301f34613bff24a8e35b5455884f2d83d8 to < 2fd5ad3f310de22836cdacae919dd99d758a1f1baffected
  • 78e1317a174edbfd1182599bf76c092a2877672caffected
  • 5.15.84 to < 5.15.165affected
  • 6.0.14 to < 6.1affected

Linux Linux

Default version status: affected

  • 6.1affected
  • 0 to < 6.1unaffected
  • 5.15.165 to ≤ 5.15.*unaffected
  • 6.1.103 to ≤ 6.1.*unaffected
  • 6.6.44 to ≤ 6.6.*unaffected
  • 6.10.3 to ≤ 6.10.*unaffected
  • 6.11 to ≤ *unaffected

References