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

[Kenji Kaneshige]

Alex Chiang wrote:
> * Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>:
> > Alex Chiang wrote:
> > > * Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>:
> > > > 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.

You're welcome.

Just in case, my patch is just for testing, and it is very buggy
(no destroy operation, lack of module_put() in error code path,
and so on). Please consider it as just for testing.

Thanks,
Kenji Kaneshige



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