Re: [PATCH 0/4] [GIT PULL] tracing: recursion and compile fixes

[Steven Rostedt]

On Mon, 20 Apr 2009, Frederic Weisbecker wrote:
> > > 
> > 
> > Hmm, doesn't the trace wakeup test if the runqueue lock is locked or not?
> > 
> > -- Steve
> > 
> 
> 
> Hmm, yes it does but that's not the first time we meet this problem
> (sched switch event tracing recursions by the past). So either the
> test doesn't work well or this is about another lock that
> wake_up_common takes...

Ug, it is the task's rq lock. Not the current rq lock. wakeup takes the 
runqueue lock of the task. The "runqueue_is_locked" only tests the lock of 
current CPU, which is not what we can have.

Thus, the function tracer (gag, and probably the event tracing!) should 
not call wakeups.

-- Steve

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