linux-kernel - Re: [PATCH v5 09/13] PCI: Introduce /sys/bus/pci/devices/.../remove

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Message-ID: <20090325052048.GA1584@ldl.fc.hp.com>
Date:	Tue, 24 Mar 2009 23:20:48 -0600
From:	Alex Chiang <achiang@...com>
To:	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
Cc:	jbarnes@...tuousgeek.org, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org, Trent Piepho <xyzzy@...akeasy.org>
Subject: Re: [PATCH v5 09/13] PCI: Introduce /sys/bus/pci/devices/.../remove

* Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>:
> Alex Chiang wrote:
> > * Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>:
> >> I still have the following kernel error messages in testing with your
> >> latest set of patches (Jesse's linux-next). The test case is removing
> >> e1000e device or its parent bridge by "echo 1 > /sys/bus/pci/devices/
> >> .../remove".
> >>
> >> [  537.379995] =============================================
> >> [  537.380124] [ INFO: possible recursive locking detected ]
> >> [  537.380128] 2.6.29-rc8-kk #1
> >> [  537.380128] ---------------------------------------------
> >> [  537.380128] events/4/56 is trying to acquire lock:
> >> [  537.380128]  (events){--..}, at: [<ffffffff80257fc0>] flush_workqueue+0x0/0xa0
> >> [  537.380128]
> >> [  537.380128] but task is already holding lock:
> >> [  537.380128]  (events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
> >> [  537.380128]
> >> [  537.380128] other info that might help us debug this:
> >> [  537.380128] 3 locks held by events/4/56:
> >> [  537.380128]  #0:  (events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
> >> [  537.380128]  #1:  (&ss->work){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
> >> [  537.380128]  #2:  (pci_remove_rescan_mutex){--..}, at: [<ffffffff803c10d1>] remove_callback+0x21/0x40
> > 
> > I still cannot reproduce this lockdep issue, even using your
> > .config with an e1000e device on an x86_64 kernel. :(
> > 
> > I tried removing the endpoint, an intermediate bridge device, and
> > the parent bus. I don't know what I'm doing wrong...
> > 
> 
> I don't know either...
> The reproducibility is 100% on my environment. The steps are
> just boot the system and remove the device.
> 
> > Can you please try this patch though, and see if it fixes the
> > warning? It applies on top of my other sysfs patch that
> > introduces a mutex in sysfs_schedule_callback.
> 
> Anyway, I confirmed the kernel error messages were gone with
> the patch against sysfs. Note that I used the following patch
> I made for testing instead since your patch could not be
> applied to Jesse's linux-next. 

Great, thank you for testing Kenji-san.

/ac

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