Re: [Linux-v4.6-rc1] ext4: WARNING: CPU: 2 PID: 2692 at kernel/locking/lockdep.c:2017 __lock_acquire+0x180e/0x2260

From: Peter Zijlstra
Date: Wed Mar 30 2016 - 08:44:07 EST


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@xxxxxxxxxxxxx> 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?