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Date: Wed, 30 Mar 2016 14:43:56 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>,
        Alfredo Alvarez Fernandez <alfredoalvarezfernandez@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        "Theodore Ts'o" <tytso@mit.edu>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [Linux-v4.6-rc1] ext4: WARNING: CPU: 2 PID: 2692 at
 kernel/locking/lockdep.c:2017 __lock_acquire+0x180e/0x2260
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On Wed, Mar 30, 2016 at 11:49:57AM +0200, Sedat Dilek wrote:
> On Wed, Mar 30, 2016 at 11:36 AM, Peter Zijlstra <peterz@infradead.org> wrote:

> > OK, so while the code in check_no_collision() seems sensible, it relies
> > on borken bits.
> >
> > The whole chain_hlocks and /proc/lockdep_chains stuff appears to have
> > been buggered from the start.
> >
> > The below patch should fix this.
> >
> 
> checkpatch.pl says...
> 
> WARNING: Prefer seq_puts to seq_printf
> #124: FILE: kernel/locking/lockdep_proc.c:145:
> +                       seq_printf(m, "(buggered) ");

Yeah, sod checkpatch ;-)

What's in your /proc/lockdep_stats file?