ab711fe082
Jiri reported: | | - once an event is created by sys_perf_event_open, task context | is created and it stays even if the event is closed, until the | task is finished ... thats what I see in code and I assume it's | correct | | - when the task opens event, perf_sched_events jump label is | incremented and following callbacks are started from scheduler | | __perf_event_task_sched_in | __perf_event_task_sched_out | | These callback *in/out set/unset cpuctx->task_ctx value to the | task context. | | - close is called on event on CPU 0: | - the task is scheduled on CPU 0 | - __perf_event_task_sched_in is called | - cpuctx->task_ctx is set | - perf_sched_events jump label is decremented and == 0 | - __perf_event_task_sched_out is not called | - cpuctx->task_ctx on CPU 0 stays set | | - exit is called on CPU 1: | - the task is scheduled on CPU 1 | - perf_event_exit_task is called | - task_ctx_sched_out unsets cpuctx->task_ctx on CPU 1 | - put_ctx destroys the context | | - another call of perf_rotate_context on CPU 0 will use invalid | task_ctx pointer, and eventualy panic. | Cure this the simplest possibly way by partially reverting the jump_label optimization for the sched_out case. Reported-and-tested-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: <stable@kernel.org> # .37+ LKML-Reference: <1301520405.4859.213.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu> |
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| acpi | ||
| asm-generic | ||
| crypto | ||
| drm | ||
| keys | ||
| linux | ||
| math-emu | ||
| media | ||
| mtd | ||
| net | ||
| pcmcia | ||
| rdma | ||
| rxrpc | ||
| scsi | ||
| sound | ||
| staging | ||
| target | ||
| trace | ||
| video | ||
| xen | ||
| Kbuild | ||