From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Sasha Levin <levinsasha928@gmail.com>
Cc: Dave Jones <davej@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: RCU idle CPU detection is broken in linux-next
Date: Wed, 19 Sep 2012 10:06:48 -0700 [thread overview]
Message-ID: <20120919170648.GF2455@linux.vnet.ibm.com> (raw)
In-Reply-To: <5059F458.3000407@gmail.com>
On Wed, Sep 19, 2012 at 06:35:36PM +0200, Sasha Levin wrote:
> On 09/19/2012 05:39 PM, Paul E. McKenney wrote:
> > On Wed, Sep 12, 2012 at 07:56:48PM +0200, Sasha Levin wrote:
> >> > Hi Paul,
> >> >
> >> > While fuzzing using trinity inside a KVM tools guest, I've managed to trigger
> >> > "RCU used illegally from idle CPU!" warnings several times.
> >> >
> >> > There are a bunch of traces which seem to pop exactly at the same time and from
> >> > different places around the kernel. Here are several of them:
> > Hello, Sasha,
> >
> > OK, interesting. Could you please try reproducing with the diagnostic
> > patch shown below?
>
> Sure - here are the results (btw, it reproduces very easily):
>
> [ 13.525119] ================================================
> [ 13.527165] [ BUG: lock held when returning to user space! ]
> [ 13.528752] 3.6.0-rc6-next-20120918-sasha-00002-g190c311-dirty #362 Tainted: GW
> [ 13.531314] ------------------------------------------------
> [ 13.532918] init/1 is leaving the kernel with locks still held!
> [ 13.534574] 1 lock held by init/1:
> [ 13.535533] #0: (rcu_idle){.+.+..}, at: [<ffffffff811c36d0>]
> rcu_eqs_enter_common+0x1a0/0x9a0
>
> I'm basically seeing lots of the above, so I can't even get to the point where I
> get the previous lockdep warnings.
OK, that diagnostic patch was unhelpful. Back to the drawing board...
Thanx, Paul
next prev parent reply other threads:[~2012-09-19 17:25 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-12 17:56 RCU idle CPU detection is broken in linux-next Sasha Levin
2012-09-19 15:39 ` Paul E. McKenney
2012-09-19 16:35 ` Sasha Levin
2012-09-19 17:06 ` Paul E. McKenney [this message]
2012-09-19 22:27 ` Sasha Levin
2012-09-20 7:33 ` Michael Wang
2012-09-20 7:44 ` Sasha Levin
2012-09-20 8:14 ` Michael Wang
2012-09-20 15:23 ` Paul E. McKenney
2012-09-21 9:30 ` Sasha Levin
2012-09-21 12:13 ` Paul E. McKenney
2012-09-21 13:26 ` Sasha Levin
2012-09-21 15:12 ` Paul E. McKenney
2012-09-21 15:18 ` Sasha Levin
2012-09-22 8:26 ` Sasha Levin
2012-09-22 15:09 ` Paul E. McKenney
2012-09-22 15:20 ` Paul E. McKenney
2012-09-22 15:40 ` Sasha Levin
2012-09-22 15:56 ` Paul E. McKenney
2012-09-22 17:50 ` Sasha Levin
2012-09-22 21:27 ` Paul E. McKenney
2012-09-23 0:21 ` Paul E. McKenney
2012-09-23 5:39 ` Sasha Levin
2012-09-24 21:29 ` Frederic Weisbecker
2012-09-24 22:47 ` Sasha Levin
2012-09-24 22:54 ` Sasha Levin
2012-09-24 23:06 ` Frederic Weisbecker
2012-09-24 23:10 ` Sasha Levin
2012-09-24 23:35 ` Frederic Weisbecker
2012-09-24 23:41 ` Frederic Weisbecker
2012-09-25 4:04 ` Paul E. McKenney
2012-09-25 11:59 ` Frederic Weisbecker
2012-09-25 13:04 ` Paul E. McKenney
2012-09-26 14:56 ` Frederic Weisbecker
2012-09-26 16:26 ` Paul E. McKenney
2012-09-25 12:06 ` Frederic Weisbecker
2012-09-25 18:28 ` Sasha Levin
2012-09-25 18:36 ` Paul E. McKenney
2012-09-26 15:46 ` Frederic Weisbecker
2012-09-26 16:59 ` Paul E. McKenney
2012-09-26 14:58 ` Frederic Weisbecker
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