Commit 0203026b authored May 17, 2009 by Ingo Molnar

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>

parent 856d56b9

kernel/exit.c

+7 −6

Original line number	Diff line number	Diff line
		@@ -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);

Admin message