perf_counter: Robustify counter-free logic

This fixes a nasty crash and highlights a bug that we were
freeing failed-fork() counters incorrectly.

(the fix for that will come separately)

[ Impact: fix crashes/lockups with inherited counters ]

Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2009-05-17 11:08:41 +02:00
parent 3f4dee2273
commit 012b84dae1

View file

@ -1004,6 +1004,10 @@ static void __perf_counter_task_sched_out(struct perf_counter_context *ctx)
if (!cpuctx->task_ctx) if (!cpuctx->task_ctx)
return; return;
if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
return;
__perf_counter_sched_out(ctx, cpuctx); __perf_counter_sched_out(ctx, cpuctx);
cpuctx->task_ctx = NULL; cpuctx->task_ctx = NULL;
} }