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Date: Fri, 10 Jul 2015 15:57:46 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
        Ingo Molnar <mingo@elte.hu>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Waiman Long <Waiman.Long@hp.com>
Subject: Re: [BUG][tip/master] kernel panic while locking selftest at
 qspinlock_paravirt.h:137!
Message-ID: <20150710135746.GA13461@gmail.com>
References: <559FAD5E.3080309@hitachi.com>
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* Peter Zijlstra <peterz@infradead.org> wrote:

> On Fri, Jul 10, 2015 at 08:32:46PM +0900, Masami Hiramatsu wrote:
> 
> >                     double unlock:
> > ------------[ cut here ]------------
> > kernel BUG at /home/mhiramat/ksrc/linux-3/kernel/locking/qspinlock_paravirt.h:137!
> 
> > Call Trace:
> >  [<ffffffff81114a59>] __raw_callee_save___pv_queued_spin_unlock+0x11/0x1e
> >  [<ffffffff81117133>] ? do_raw_spin_unlock+0xfa/0x10c
> >  [<ffffffff817cd3f7>] _raw_spin_unlock+0x44/0x64
> >  [<ffffffff814603ee>] double_unlock_spin+0x3d/0x46
> 
> Cute, but somewhat expected. A double unlock really is a BUG and the PV
> spinlock code cannot deal with it.
> 
> Do we want to make double unlock non-fatal unconditionally?

No, just don't BUG() out, don't crash the system - generate a warning?

Thanks,

	Ingo
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