From 012b84dae17126d8b5d159173091eb3db5a2bc43 Mon Sep 17 00:00:00 2001 From: Ingo Molnar <mingo@elte.hu> Date: Sun, 17 May 2009 11:08:41 +0200 Subject: [PATCH] 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> --- kernel/perf_counter.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index eb346048f00f..616c52426b32 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1004,6 +1004,10 @@ static void __perf_counter_task_sched_out(struct perf_counter_context *ctx) if (!cpuctx->task_ctx) return; + + if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) + return; + __perf_counter_sched_out(ctx, cpuctx); cpuctx->task_ctx = NULL; }