From: Dave Young <hidave.darkstar@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Alan Stern <stern@rowland.harvard.edu>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Greg KH <gregkh@suse.de>, Thomas Gleixner <tglx@linutronix.de>,
Cong Wang <amwang@redhat.com>,
Kernel development list <linux-kernel@vger.kernel.org>,
Tejun Heo <tj@kernel.org>, Miles Lane <miles.lane@gmail.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Larry Finger <Larry.Finger@lwfinger.net>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [Patch 0/2] sysfs: fix s_active lockdep warning
Date: Sun, 7 Feb 2010 17:22:16 +0800 [thread overview]
Message-ID: <20100207092216.GA2585@darkstar> (raw)
In-Reply-To: <1265384517.30057.50.camel@laptop>
On Fri, Feb 05, 2010 at 04:41:57PM +0100, Peter Zijlstra wrote:
> On Fri, 2010-02-05 at 10:30 -0500, Alan Stern wrote:
> > On Fri, 5 Feb 2010, Peter Zijlstra wrote:
> >
> > > Right, so this device stuff is much more complicated than I was led to
> > > believe ;-)
> >
> > Haven't I told you all along that tree-structured locking is
> > complicated? :-)
>
> Well, regular tree's aren't all that complicated, but multiple
> inter-locking trees is a whole different story indeed.
>
I ever tried converting device semaphore to mutex, but failed with same issue.
At least now there's no lockdep solution for it, so I recommend revert
the mutex converting patch.
following lockdep warning with rc6-mm1:
[ 0.397123]
[ 0.397124] =============================================
[ 0.397359] [ INFO: possible recursive locking detected ]
[ 0.397480] 2.6.33-rc6-mm1 #1
[ 0.397596] ---------------------------------------------
[ 0.397717] swapper/1 is trying to acquire lock:
[ 0.397836] (&dev->mutex){+.+...}, at: [<c12662e4>] __driver_attach+0x38/0x63
[ 0.398162]
[ 0.398162] but task is already holding lock:
[ 0.398393] (&dev->mutex){+.+...}, at: [<c12662d8>] __driver_attach+0x2c/0x63
[ 0.399999]
[ 0.399999] other info that might help us debug this:
[ 0.399999] 1 lock held by swapper/1:
[ 0.399999] #0: (&dev->mutex){+.+...}, at: [<c12662d8>] __driver_attach+0x2c/0x63
[ 0.399999]
[ 0.399999] stack backtrace:
[ 0.399999] Pid: 1, comm: swapper Not tainted 2.6.33-rc6-mm1 #1
[ 0.399999] Call Trace:
[ 0.399999] [<c13d5851>] ? printk+0xf/0x11
[ 0.399999] [<c105460c>] __lock_acquire+0x880/0xc0d
[ 0.399999] [<c13d66e4>] ? __mutex_unlock_slowpath+0xf0/0xff
[ 0.399999] [<c1054a34>] lock_acquire+0x9b/0xb8
[ 0.399999] [<c12662e4>] ? __driver_attach+0x38/0x63
[ 0.399999] [<c13d685c>] __mutex_lock_common+0x35/0x2f2
[ 0.399999] [<c12662e4>] ? __driver_attach+0x38/0x63
[ 0.399999] [<c13d6bb7>] mutex_lock_nested+0x30/0x38
[ 0.399999] [<c12662e4>] ? __driver_attach+0x38/0x63
[ 0.399999] [<c12662e4>] __driver_attach+0x38/0x63
[ 0.399999] [<c1265a43>] bus_for_each_dev+0x3d/0x67
[ 0.399999] [<c1265f8f>] driver_attach+0x14/0x16
[ 0.399999] [<c12662ac>] ? __driver_attach+0x0/0x63
[ 0.399999] [<c126541c>] bus_add_driver+0xc4/0x20c
[ 0.399999] [<c1266553>] driver_register+0x8b/0xeb
[ 0.399999] [<c11d8e3a>] acpi_bus_register_driver+0x3a/0x3c
[ 0.399999] [<c165dc9a>] acpi_ec_init+0x2b/0x4a
[ 0.399999] [<c165daf8>] acpi_init+0x289/0x2c8
[ 0.399999] [<c165d86f>] ? acpi_init+0x0/0x2c8
[ 0.399999] [<c1001139>] do_one_initcall+0x4c/0x13f
[ 0.399999] [<c163d315>] kernel_init+0x123/0x174
[ 0.399999] [<c163d1f2>] ? kernel_init+0x0/0x174
[ 0.399999] [<c10035ba>] kernel_thread_helper+0x6/0x10
>
> --
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next prev parent reply other threads:[~2010-02-07 9:22 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-29 7:01 [Patch 0/2] sysfs: fix s_active lockdep warning Amerigo Wang
2010-01-29 7:02 ` [Patch 1/2] sysfs: add support for lockdep subclasses to s_active Amerigo Wang
2010-01-29 7:02 ` [PATCH 2/2] sysfs: fix the incomplete part of subclass support for s_active Amerigo Wang
2010-01-29 7:21 ` [Patch 0/2] sysfs: fix s_active lockdep warning Eric W. Biederman
2010-01-29 8:38 ` Cong Wang
2010-01-29 13:44 ` Eric W. Biederman
2010-01-29 14:22 ` Greg KH
2010-01-29 17:57 ` Peter Zijlstra
2010-01-29 18:10 ` Greg KH
2010-01-29 18:14 ` Peter Zijlstra
2010-01-29 18:21 ` Greg KH
2010-01-29 20:10 ` Peter Zijlstra
2010-01-29 20:30 ` Eric W. Biederman
2010-02-04 11:38 ` Peter Zijlstra
2010-02-04 16:35 ` Alan Stern
2010-02-04 16:41 ` Peter Zijlstra
2010-02-04 18:37 ` Alan Stern
2010-02-05 10:18 ` Peter Zijlstra
2010-02-05 15:30 ` Alan Stern
2010-02-05 15:41 ` Peter Zijlstra
2010-02-07 9:22 ` Dave Young [this message]
2010-02-08 3:08 ` Cong Wang
2010-02-08 3:14 ` Dave Young
2010-02-08 3:30 ` Cong Wang
2010-02-08 3:06 ` Cong Wang
2010-02-08 15:38 ` Alan Stern
2010-02-04 16:46 ` Peter Zijlstra
2010-02-04 18:40 ` Alan Stern
2010-02-05 3:09 ` Cong Wang
2010-02-05 4:06 ` Alan Stern
2010-02-04 16:46 ` Greg KH
2010-02-04 16:59 ` Thomas Gleixner
2010-02-26 19:36 ` Alan Stern
2010-02-26 20:54 ` Thomas Gleixner
2010-02-05 3:43 ` Cong Wang
2010-02-05 8:55 ` Eric W. Biederman
2010-01-29 20:25 ` Eric W. Biederman
2010-01-30 5:30 ` Greg KH
2010-01-29 18:02 ` Peter Zijlstra
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