perf_counter: fix threaded task exit

Flushing counters in __exit_signal() with irqs disabled is not
a good idea as perf_counter_exit_task() acquires mutexes. So
flush it before acquiring the tasklist lock.

(Note, we still need a fix for when the PID has been unhashed.)

[ Impact: fix crash with inherited counters ]

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2009-05-17 11:24:08 +02:00
parent 856d56b9e5
commit 0203026b58
1 changed files with 7 additions and 6 deletions

View File

@ -128,12 +128,6 @@ static void __exit_signal(struct task_struct *tsk)
sig = NULL; /* Marker for below. */
}
/*
* Flush inherited counters to the parent - before the parent
* gets woken up by child-exit notifications.
*/
perf_counter_exit_task(tsk);
__unhash_process(tsk);
/*
@ -183,6 +177,13 @@ repeat:
atomic_dec(&__task_cred(p)->user->processes);
proc_flush_task(p);
/*
* Flush inherited counters to the parent - before the parent
* gets woken up by child-exit notifications.
*/
perf_counter_exit_task(p);
write_lock_irq(&tasklist_lock);
tracehook_finish_release_task(p);
__exit_signal(p);