Re: [GIT PULL] tracing: use raw spinlocks for trace_vprintk

From: Steven Rostedt
Date: Wed Mar 11 2009 - 14:32:37 EST



On Wed, 11 Mar 2009, Ingo Molnar wrote:

>
> * Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> > On Tue, 2009-03-10 at 21:26 -0400, Steven Rostedt wrote:
> >
> > > commit 80370cb758e7ca2692cd9fb5e413d970b1f4b2b2
> > > Author: Steven Rostedt <srostedt@xxxxxxxxxx>
> > > Date: Tue Mar 10 17:16:35 2009 -0400
> > >
> > > tracing: use raw spinlocks for trace_vprintk
> > >
> > > Impact: prevent locking up by lockdep tracer
> > >
> > > The lockdep tracer uses trace_vprintk and thus trace_vprintk can not
> > > call back into lockdep without locking up.
> >
> > Hmm, I did this when I posted the lockdep tracepoints, so someone then
> > did a bad copy/paste job when renaming ftrace_printk or something?
> >
> > See efed792d6738964f399a508ef9e831cd60fa4657
>
> What's the conclusion in this thread? I'm holding the pull
> until there's agreement.

I believe the conclusion is that Peter's changes got removed when Frederic
removed the old printk version. But his new version did not have the
changes.

My changes are basically the same as Peter's except that I did not do
anything with the local_irq_save, since I do not think those are needed.

Peter,

Are you fine with the change? I guess it's up to you now.

-- Steve

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