From: Dave Jones <davej@codemonkey.org.uk>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linux Kernel <linux-kernel@vger.kernel.org>,
linux-pm@vger.kernel.org
Subject: Re: cpufreq/ondemand: unpinning an unpinned lock.
Date: Thu, 16 Jul 2015 08:42:41 -0400 [thread overview]
Message-ID: <20150716124241.GA20320@codemonkey.org.uk> (raw)
In-Reply-To: <20150716051150.GA15404@linux>
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
> > > CPU: 1 PID: 29529 Comm: kworker/1:1 Not tainted 4.2.0-rc2-think+ #3
> > > Workqueue: events od_dbs_timer
> > > 0000000000000009 ffff880094d5baa8 ffffffffae7f5e6f 0000000000000007
> > > ffff880094d5baf8 ffff880094d5bae8 ffffffffae07b91a 0000000000000118
> > > 00000000000000e0 ffff880507bd5c58 0000000000000092 0000000000000004
> > > Call Trace:
> > > [<ffffffffae7f5e6f>] dump_stack+0x4f/0x7b
> > > [<ffffffffae07b91a>] warn_slowpath_common+0x8a/0xc0
> > > [<ffffffffae07b996>] warn_slowpath_fmt+0x46/0x50
> > > [<ffffffffae0d0ec9>] lock_unpin_lock+0x109/0x110
> > > [<ffffffffae7f93cc>] __schedule+0x3ac/0xb60
> > > [<ffffffffae7f9c41>] schedule+0x41/0x90
> > > [<ffffffffae7f9ff8>] schedule_preempt_disabled+0x18/0x30
> > > [<ffffffffae7fbcef>] mutex_lock_nested+0x16f/0x3e0
> > > [<ffffffffae69207f>] ? gov_queue_work+0x2f/0xf0
> > > [<ffffffffae690ec7>] ? od_check_cpu+0x57/0xd0
> > > [<ffffffffae69207f>] ? gov_queue_work+0x2f/0xf0
> > > [<ffffffffae69207f>] gov_queue_work+0x2f/0xf0
> > > [<ffffffffae6918dd>] od_dbs_timer+0xbd/0x150
>
> I don't know why this will happen. Just to confirm, you are getting
> this over 4.2-rc(1 or 2)? And you weren't getting these on 4.1 at all?
> And its always reproducible? How ?
I've hit it once, on rc2. I didn't have a lot of time for testing rc1.
> There have been races in cpufreq core since sometime and what got
> pushed in 4.2-rc1 is just half of the fix. The other half is present
> here:
>
> http://marc.info/?i=cover.1434713657.git.viresh.kumar%40linaro.org
>
> Please try this and let us know if things work well or not.
Sure. Though proving the absense of a bug like this is always fun.
Dave
next prev parent reply other threads:[~2015-07-16 12:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-15 22:04 cpufreq/ondemand: unpinning an unpinned lock Dave Jones
2015-07-16 0:13 ` Rafael J. Wysocki
2015-07-16 5:11 ` Viresh Kumar
2015-07-16 12:42 ` Dave Jones [this message]
2015-07-22 0:46 ` Stephen Boyd
2015-07-22 9:02 ` Peter Zijlstra
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