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Date: Fri, 16 May 2014 14:14:47 -0400
From: "Carlos O'Donell" <carlos@redhat.com>
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To: Peter Zijlstra <peterz@infradead.org>
CC: Darren Hart <dvhart@linux.intel.com>, Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>, Dave Jones <davej@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Darren Hart <darren@dvhart.com>, Davidlohr Bueso <davidlohr@hp.com>,
        Ingo Molnar <mingo@kernel.org>, Steven Rostedt <rostedt@goodmis.org>,
        Clark Williams <williams@redhat.com>,
        Paul McKenney <paulmck@linux.vnet.ibm.com>,
        Lai Jiangshan <laijs@cn.fujitsu.com>,
        Roland McGrath <roland@hack.frob.com>,
        Jakub Jelinek <jakub@redhat.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: [patch 0/3] futex/rtmutex: Fix issues exposed by trinity
References: <20140512190438.314125476@linutronix.de> <20140513035404.GA68181@dvhart-mac01.local> <537313FD.4000306@redhat.com> <20140514092203.GE30445@twins.programming.kicks-ass.net> <5373DD6F.40506@redhat.com> <20140515080753.GB30445@twins.programming.kicks-ass.net>
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On 05/15/2014 04:07 AM, Peter Zijlstra wrote:
> On Wed, May 14, 2014 at 05:17:35PM -0400, Carlos O'Donell wrote:
>>> No, its perfectly fine to have a lock sequence abort with -EDEADLK.
>>> Userspace should release its locks and re-attempt.
>>
>> I agree. If I can prove that it's actually a deadlock, and
>> that unlock/relock will work to fix it, then we can arrange for glibc
>> to return EDEADLK.
> 
> The only reason the kernel would return EDEADLK is because its walked
> the lock graph and determined its well, a deadlock.

Perfect. No further comments from me then.

Cheers,
Carlos.