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Date: Fri, 2 May 2014 21:12:53 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Vince Weaver <vincent.weaver@maine.edu>
cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>,
        linux-kernel@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [perf] more perf_fuzzer memory corruption
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On Fri, 2 May 2014, Vince Weaver wrote:
> On Fri, 2 May 2014, Peter Zijlstra wrote:
> 
> > On Fri, May 02, 2014 at 12:43:17PM -0400, Vince Weaver wrote:
> > > On Fri, 2 May 2014, Peter Zijlstra wrote:
> > > 
> > > > In principle the vfs file refcounting should be responsible for that.
> > > > But I'll go over it in a bit.
> > > 
> > > The poll code is ancient and the C-parser in my head really can't handle 
> > > it very well.
> > 
> > Yeah, that code isn't my favourite part either..
> > 
> > > Anyway for completeness this is the kind of thing I'm seeing.
> > > The poll() manpage isn't very clear about what is supposed to happen if 
> > > you poll() on a closed file descriptor.
> > 
> >               POLLNVAL
> >                      Invalid request: fd not open (output only).
> > 
> > Seems applicable..
> 
> You're right and it seems to return that properly, so having poll be 
> active might just be a weird co-incidence.
> 
> > Also, could you send your entire diff this way so we're more or less
> > staring at the same code again?
> 
> that last test I ran was just 3.15-rc1 plus the last patch you sent,
> plus a patch to allow -pg on the event.c file, plus an unrelated one that 
> works around the current make-kpkg debian breakage.

Hmm, and where comes the WARN_ON in _free_event() from? That's not in
Peters last patch.

Thanks,

	tglx