Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1590497

Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff

Show all headers | View raw

On Wed, Mar 01, 2017 at 04:11:48PM +0000, Chris Wilson wrote:
> On Wed, Mar 01, 2017 at 04:54:14PM +0100, Peter Zijlstra wrote:
> > On Wed, Mar 01, 2017 at 11:40:43PM +0800, Fengguang Wu wrote:
> > > Thanks for the patch! I applied the patch on top of "locking/ww_mutex:
> > > Add kselftests for ww_mutex stress", and find no "bad unlock balance
> > > detected" but this warning. Attached is the new dmesg which is a bit
> > > large due to lots of repeated errors.
> > 
> > So with all the various patches it works for me.
> > 
> > I also have the following on top; which I did when I was looking through
> > this code trying to figure out wth was happening.
> > 
> > Chris, does this make sense to you?
> > 
> > It makes each loop a fully new 'instance', otherwise we'll never update
> > the ww_class->stamp and the threads will aways have the same order.
> 
> Sounds ok, I just thought the stamp order of the threads was
> immaterial - with each test doing a different sequence of locks and each
> being identical in behaviour, it would not matter which had priority,
> there would have be some shuffling no matter waht. However, for the
> purpose of testing, having each iteration be a new locking instance does
> make it behaviour more like a typical user.

Correcting myself, the workers didn't reorder the locks, so changing the
stamp does make the test more interesting.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at  kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff Peter Zijlstra <peterz@infradead.org> - 2017-02-27 12:30 +0100
  Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at  kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff Peter Zijlstra <peterz@infradead.org> - 2017-02-27 12:50 +0100
    Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at  kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff Boqun Feng <boqun.feng@gmail.com> - 2017-03-01 16:10 +0100
      Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at  kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff Peter Zijlstra <peterz@infradead.org> - 2017-03-01 16:20 +0100
      Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at  kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff Peter Zijlstra <peterz@infradead.org> - 2017-03-01 17:00 +0100
        Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at  kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff Chris Wilson <chris@chris-wilson.co.uk> - 2017-03-01 17:20 +0100
          Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at  kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff Chris Wilson <chris@chris-wilson.co.uk> - 2017-03-01 17:30 +0100
            Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at  kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff Fengguang Wu <fengguang.wu@intel.com> - 2017-03-01 18:50 +0100
            Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at  kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff Peter Zijlstra <peterz@infradead.org> - 2017-03-01 22:50 +0100
      Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at  kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff Peter Zijlstra <peterz@infradead.org> - 2017-03-01 17:00 +0100
        Re: [locking/ww_mutex] 2a0c112828 WARNING: CPU: 0 PID: 18 at  kernel/locking/mutex.c:305 __ww_mutex_wakeup_for_backoff Fengguang Wu <fengguang.wu@intel.com> - 2017-03-01 17:00 +0100
      [tip:locking/urgent] locking/ww_mutex: Adjust the lock number for  stress test tip-bot for Boqun Feng <tipbot@zytor.com> - 2017-03-02 09:50 +0100

csiph-web