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From: Peter Zijlstra <peterz@infradead.org>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: linux-block <linux-block@vger.kernel.org>,
	Omar Sandoval <osandov@fb.com>, Jens Axboe <axboe@fb.com>,
	LKP <lkp@01.org>
Subject: Re: [blk_mq_register_hctx] 29dee3c03a WARNING: CPU: 0 PID: 5 at lib/refcount.c:114 refcount_inc
Date: Tue, 28 Feb 2017 08:48:02 +0100	[thread overview]
Message-ID: <20170228074802.GC6500@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20170228041117.hbqqyczf5bnypqmc@wfg-t540p.sh.intel.com>

On Tue, Feb 28, 2017 at 12:11:17PM +0800, Fengguang Wu wrote:
> Hello,
> 
> FYI, an old blk_mq bug triggers new warnings on this commit. It's very
> reproducible and you may try the attached reproduce-* script.
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> 
> commit 29dee3c03abce04cd527878ef5f9e5f91b7b83f4
> Author:     Peter Zijlstra <peterz@infradead.org>
> AuthorDate: Fri Feb 10 16:27:52 2017 +0100
> Commit:     Ingo Molnar <mingo@kernel.org>
> CommitDate: Fri Feb 24 09:02:10 2017 +0100
> 
>      locking/refcounts: Out-of-line everything
>      
>      Linus asked to please make this real C code.
>      
>      And since size then isn't an issue what so ever anymore, remove the
>      debug knob and make all WARN()s unconditional.
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I suspect that if you revert, but enable CONFIG_DEBUG_REFCOUNT you'd
have gotten the same splats..


I'll go have a look though, something looks buggered.

       reply	other threads:[~2017-02-28  8:14 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20170228041117.hbqqyczf5bnypqmc@wfg-t540p.sh.intel.com>
2017-02-28  7:48 ` Peter Zijlstra [this message]
2017-02-28  8:17 ` [blk_mq_register_hctx] 29dee3c03a WARNING: CPU: 0 PID: 5 at lib/refcount.c:114 refcount_inc Peter Zijlstra
2017-02-28  8:35   ` Fengguang Wu
2017-02-28  8:52     ` Omar Sandoval
2017-02-28  8:38   ` Peter Zijlstra
2017-02-28  9:45     ` Peter Zijlstra

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