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Date: Mon, 23 Feb 2015 18:02:30 -0300
Message-ID: <CAMiJ5CXFUmZVhqtthFSo_68sv9oLtadHWYvum=mnJv9ECLf9Fw@mail.gmail.com>
Subject: Re: smp_call_function_single lockups
From: Rafael David Tinoco <inaddy@ubuntu.com>
To: Peter Zijlstra <peterz@infradead.org>
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>,
        Christopher Arges <chris.j.arges@canonical.com>,
        Dave Jones <davej@redhat.com>
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>
> [11396.096002] Hardware name: OpenStack Foundation OpenStack Nova, BIOS Bochs 01/01/2011
>
> But its a virtual machine right? Its not running bare metal, its running
> a !virt kernel on a virt machine, so maybe some of the virt muck is
> borked?
>
> A very subtly broken APIC emulation would be heaps of 'fun'.

Indeed, I'll dig hypervisor changes... Anyway, this initial stack
trace was first seen during the "frequent lockups in 3.18rc4"
discussion:

https://lkml.org/lkml/2014/11/14/656

RIP: 0010:[<ffffffff9c11e98a>]  [<ffffffff9c11e98a>]
generic_exec_single+0xea/0x1d0

At that time seen by Dave Jones, and running bare metal (if i remember
correctly).

-- 
Rafael Tinoco