Date: Thu, 19 Feb 2015 17:16:04 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Rafael David Tinoco <inaddy@ubuntu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, Jens Axboe <axboe@kernel.dk>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Gema Gomez <gema.gomez-solano@canonical.com>,
        chris.j.arges@canonical.com
Subject: Re: smp_call_function_single lockups
Message-ID: <20150219161604.GB17717@twins.programming.kicks-ass.net>
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On Thu, Feb 19, 2015 at 01:42:39PM -0200, Rafael David Tinoco wrote:
> Linus, Peter, Thomas
> 
> Just a quick feedback, We were able to reproduce the lockup with this
> proposed patch (3.19 + patch). Unfortunately we had problems with the
> core file and I have only the stack trace for now but I think we are
> able to reproduce it again and provide more details (sorry for the
> delay... after a reboot it took some days for us to reproduce this
> again).
> 
> It looks like RIP is still smp_call_function_single.

So Linus' patch mostly fixes smp_call_function_single_async() which is
not what you're using.

It would be very good to see traces of other CPUs; if for some reason
the target CPU doesn't get around to running your callback, then we'll
forever wait on it.

loaded_vmcs_clear() uses smp_call_function_single(.wait = 1), that
should work as before.
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