Re: [PATCH 0/5] [GIT PULL] updates for tip/tracing/ftrace

From: Ingo Molnar
Date: Sun Mar 22 2009 - 16:42:27 EST



* Ingo Molnar <mingo@xxxxxxx> wrote:

> found another, unrelated lockup with the event tracer:
>
> europe:/debug/tracing/events/sched/sched_wakeup_new> cat enable
> 0
> europe:/debug/tracing/events/sched/sched_wakeup_new> echo 1 > enable
> europe:/debug/tracing/events/sched/sched_wakeup_new> sync
> europe:/debug/tracing/events/sched/sched_wakeup_new> cat
> ../../../trace_pipe
> <...>-2870 [000] 688.730160: sched_wakeup_new: task
> bash:2898 [120] success=1
> <...>-2870 [001] 689.945375: sched_wakeup_new: task
> bash:2899 [120] success=1
>
> [hard lockup]

ok, tracked it down - it's the new trace_wake_up() from within
wake_up_new_task() => bad idea.

I think this was introduced via:

6eaaa5d: tracing/core: use appropriate waiting on trace_pipe

Ingo
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