lkml.org 
[lkml]   [2015]   [Jul]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: cpufreq/ondemand: unpinning an unpinned lock.
On Tue, Jul 21, 2015 at 05:46:16PM -0700, Stephen Boyd wrote:
> On 07/16/2015 05:42 AM, Dave Jones wrote:
> >On Thu, Jul 16, 2015 at 10:41:50AM +0530, Viresh Kumar wrote:
> >
> > > > > WARNING: CPU: 1 PID: 29529 at kernel/locking/lockdep.c:3497 lock_unpin_lock+0x109/0x110()
> > > > > unpinning an unpinned lock
> > > > > Call Trace:

> > > > > [<ffffffffae0d0ec9>] lock_unpin_lock+0x109/0x110
> > > > > [<ffffffffae7f93cc>] __schedule+0x3ac/0xb60
> > > > > [<ffffffffae7f9c41>] schedule+0x41/0x90
> > > > > [<ffffffffae7f9ff8>] schedule_preempt_disabled+0x18/0x30

> Lock pinning is new in v4.2-rc1. Adding Peter just in case there's some
> insight.

Hmm, weird. I've not seen it happen before.

There's potentially 3 unpin's in __schedule():

- the obvious one in the prev == next case,
- the on in context_switch(),
- the on in try_to_wake_up_local().

All 3 appear to be balanced; the first and second against the pin_lock()
at the start of __schedule() and the third against that and it repins
the lock against the first two.

Most curious.


\
 
 \ /
  Last update: 2015-07-22 11:21    [from the cache]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and my Meterkast|Read the blog