linux-kernel - Re: [sched/core] 8a8c69c327: WARNING: CPU: 0 PID: 8 at kernel/locking/lockdep.c:3548 lock

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Date:   Fri, 17 Mar 2017 15:09:09 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Wanpeng Li <kernellwp@...il.com>
Cc:     kernel test robot <fengguang.wu@...el.com>, LKP <lkp@...org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>, wfg@...ux.intel.com
Subject: Re: [sched/core] 8a8c69c327: WARNING: CPU: 0 PID: 8 at
 kernel/locking/lockdep.c:3548 lock_release

On Fri, Mar 17, 2017 at 09:24:11PM +0800, Wanpeng Li wrote:
> 2017-03-17 21:02 GMT+08:00 Wanpeng Li <kernellwp@...il.com>:
> > 2017-03-17 4:02 GMT+08:00 kernel test robot <fengguang.wu@...el.com>:
> >> Greetings,
> >>
> >> 0day kernel testing robot got the below dmesg and the first bad commit is
> >>
> >> https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched/core
> >>
> >> commit 8a8c69c32778865affcedc2111bb5d938b50516f
> >> Author:     Peter Zijlstra <peterz@...radead.org>
> >> AuthorDate: Tue Oct 4 16:04:35 2016 +0200
> >> Commit:     Ingo Molnar <mingo@...nel.org>
> >> CommitDate: Thu Mar 16 09:46:22 2017 +0100
> >>
> >>     sched/core: Add rq->lock wrappers
> >>
> >>     The missing update_rq_clock() check can work with partial rq->lock
> >>     wrappery, since a missing wrapper can cause the warning to not be
> >>     emitted when it should have, but cannot cause the warning to trigger
> >>     when it should not have.
> >>
> >>     The duplicate update_rq_clock() check however can cause false warnings
> >>     to trigger. Therefore add more comprehensive rq->lock wrappery.
> >>
> >>     Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> >>     Cc: Linus Torvalds <torvalds@...ux-foundation.org>
> >>     Cc: Mike Galbraith <efault@....de>
> >>     Cc: Peter Zijlstra <peterz@...radead.org>
> >>     Cc: Thomas Gleixner <tglx@...utronix.de>
> >>     Signed-off-by: Ingo Molnar <mingo@...nel.org>
> >
> > Please refer to: https://lkml.org/lkml/2017/3/16/1131
> 
> I have another version of patch which utilizes raw_spin_lock_irqsave()
> instead of rq_lock_irqsave() in __balance_callback() as before, which
> one do you like, Peterz?

Hurm.. the raw_spin_lock_irqsave() one I suspect. No point in pinning
and then unpinning.