Messages in this thread Patch in this message | | | Date | Mon, 12 Mar 2007 17:03:37 +0100 | From | Michal Schmidt <> | Subject | [PATCH -rt] fix preempt count underflow in user_trace_stop |
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When playing with trace_user_trigger_irq in order to trace IRQ->userspace latencies, I encountered a bug in the latency tracer. If I have wakeup_timing enabled and attempt to stop the trace in my userspace program, the system crashes. This is caused by an unbalanced preempt_enable() which underflows the preempt count.
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
diff --git a/kernel/latency_trace.c b/kernel/latency_trace.c index e07bb95..29dfb79 100644 --- a/kernel/latency_trace.c +++ b/kernel/latency_trace.c @@ -2396,7 +2396,6 @@ long user_trace_stop(void) if (current != sch.task) { __raw_spin_unlock(&sch.trace_lock); local_irq_restore(flags); - preempt_enable(); return -EINVAL; } sch.task = NULL;
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