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CVE PROGRAM SOURCE RECORDUnscored

CVE-2024-43869

perf: Fix event leak upon exec and file release

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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 exec and file release The perf pending task work is never waited upon the matching event release. In the case of a child event, released via free_event() directly, this can potentially result in a leaked event, such as in the following scenario that doesn't even require a weak IRQ work implementation to trigger: schedule() prepare_task_switch() =======> <NMI> perf_event_overflow() event->pending_sigtrap = ... irq_work_queue(&event->pending_irq) <======= </NMI> perf_event_task_sched_out() event_sched_out() event->pending_sigtrap = 0; atomic_long_inc_not_zero(&event->refcount) task_work_add(&event->pending_task) finish_lock_switch() =======> <IRQ> perf_pending_irq() //do nothing, rely on pending task work <======= </IRQ> begin_new_exec() perf_event_exit_task() perf_event_exit_event() // If is child event free_event() WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1) // event is leaked Similar scenarios can also happen with perf_event_remove_on_exec() or simply against concurrent perf_event_release(). Fix this with synchonizing against the possibly remaining pending task work while freeing the event, just like is done with remaining pending IRQ work. This means that the pending task callback neither need nor should hold a reference to the event, preventing it from ever beeing freed.

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 < 9ad46f1fef421d43cdab3a7d1744b2f43b54dae0affected
  • 517e6a301f34613bff24a8e35b5455884f2d83d8 to < ed2c202dac55423a52d7e2290f2888bf08b8ee99affected
  • 517e6a301f34613bff24a8e35b5455884f2d83d8 to < 104e258a004037bc7dba9f6085c71dad6af57ad4affected
  • 517e6a301f34613bff24a8e35b5455884f2d83d8 to < f34d8307a73a18de5320fcc6f40403146d061891affected
  • 517e6a301f34613bff24a8e35b5455884f2d83d8 to < 3a5465418f5fd970e86a86c7f4075be262682840affected
  • 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