Date: Thu, 17 Apr 2014 16:54:18 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Vince Weaver <vincent.weaver@maine.edu>
Cc: Ingo Molnar <mingo@kernel.org>, linux-kernel@vger.kernel.org,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [perf] more perf_fuzzer memory corruption
Message-ID: <20140417145418.GM11096@twins.programming.kicks-ass.net>
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 <alpine.DEB.2.10.1404161326380.19325@vincent-weaver-1.um.maine.edu>
 <alpine.DEB.2.10.1404161337350.19325@vincent-weaver-1.um.maine.edu>
 <20140417094815.GA9348@gmail.com>
 <20140417114533.GJ11096@twins.programming.kicks-ass.net>
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On Thu, Apr 17, 2014 at 10:42:47AM -0400, Vince Weaver wrote:
> On Thu, 17 Apr 2014, Ingo Molnar wrote:
> 
> > 
> > * Peter Zijlstra <peterz@infradead.org> wrote:
> > 
> > > On Thu, Apr 17, 2014 at 11:48:15AM +0200, Ingo Molnar wrote:
> > > > Is there some place where I can pick up the latestest of your fuzzer?
> > > > 
> > > > PeterZ has trouble reproducing the corruption locally - I'd like to 
> > > > run it too, maybe I have hardware that triggers it more readily.
> > > 
> > > From a few emails up:
> > > 
> > > "If you want to try running the fuzzer on your machine too just do:
> > >         git clone https://github.com/deater/perf_event_tests.git
> > >         cd fuzzer
> > >         make
> > > and then try running the "./fast_repro98.sh" script, as that's the forking
> > > workload I've been using when tracking this issue."
> 
> I have to admit the slab corruption message is a new development with 
> 3.15-rc1.

Meh.. my machine keeps locking up with 15-rc1 and your fuzzer. It looks
to get stuck a finish_task_switch() from a preemption while waiting for
a perf IPI.

Which is complete crack because we have preemption disabled over
issueing and waiting for the IPI :/

I tried reverting some of the IPI related patches, but no joy so far,
I'm about to go try a git-bisect on this.
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