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| author | Ingo Molnar <mingo@elte.hu> | 2009-05-17 11:08:41 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-05-20 00:22:24 +0200 |
| commit | 33b2fb303fe7f6b08bbb32f708e67b96eaa94a7a (patch) | |
| tree | 32ab4cb3cca6c61a2d6cf351bb8f732045464e28 /kernel | |
| parent | b68f1d2e7aa21029d73c7d453a8046e95d351740 (diff) | |
| download | linux-33b2fb303fe7f6b08bbb32f708e67b96eaa94a7a.tar.gz linux-33b2fb303fe7f6b08bbb32f708e67b96eaa94a7a.tar.bz2 linux-33b2fb303fe7f6b08bbb32f708e67b96eaa94a7a.zip | |
perf_counter: fix counter freeing logic
Fix counter lifetime bugs which explain the crashes reported by
Marcelo Tosatti and Arnaldo Carvalho de Melo.
The new rule is: flushing + freeing is only done for a task's
own counters, never for other tasks.
[ Impact: fix crashes/lockups with inherited counters ]
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reported-by: Marcelo Tosatti <mtosatti@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/exit.c | 19 | ||||
| -rw-r--r-- | kernel/perf_counter.c | 2 |
2 files changed, 9 insertions, 12 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 73affd35e76d..f9dfedd94af0 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -178,12 +178,6 @@ repeat: 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); @@ -985,6 +979,13 @@ NORET_TYPE void do_exit(long code) module_put(tsk->binfmt->module); proc_exit_connector(tsk); + + /* + * Flush inherited counters to the parent - before the parent + * gets woken up by child-exit notifications. + */ + perf_counter_exit_task(tsk); + exit_notify(tsk, group_dead); #ifdef CONFIG_NUMA mpol_put(tsk->mempolicy); @@ -1257,12 +1258,6 @@ static int wait_task_zombie(struct task_struct *p, int options, */ read_unlock(&tasklist_lock); - /* - * Flush inherited counters to the parent - before the parent - * gets woken up by child-exit notifications. - */ - perf_counter_exit_task(p); - retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; status = (p->signal->flags & SIGNAL_GROUP_EXIT) ? p->signal->group_exit_code : p->exit_code; diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 59a926d04baf..7af16d1c480f 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -3299,6 +3299,8 @@ void perf_counter_exit_task(struct task_struct *child) struct perf_counter *child_counter, *tmp; struct perf_counter_context *child_ctx; + WARN_ON_ONCE(child != current); + child_ctx = &child->perf_counter_ctx; if (likely(!child_ctx->nr_counters)) |