Re: [BUG] usb_set_device_state

[Minchan Kim]

On Sun, Feb 6, 2011 at 9:03 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> On Sunday, February 06, 2011, Rafael J. Wysocki wrote:
>> On Sunday, February 06, 2011, Alan Stern wrote:
>> > On Sun, 6 Feb 2011, Rafael J. Wysocki wrote:
>> >
>> > > On Saturday, February 05, 2011, Alan Stern wrote:
>> > > > On Sun, 6 Feb 2011, Minchan Kim wrote:
>> > > >
>> > > > > I got following message during booting mmotm-02-04.
>> > ...
>> > > > > It seems usb_set_device_state disable irq by spin_lock_irqsave.
>> > > > > But it calls device_set_wakeup_capable which ends up calling sysfs_merge_group.
>> > > > > It calls mutex_lock. :(
>> > > > >
>> > > > > Is it already known BUG?
>> > > >
>> > > > No, it was newly introduced by changes to the
>> > > > device_set_wakeup_capable() routine. ÂRafael, this sort of problem may
>> > > > occur in other places too, since previously there was no requirement
>> > > > that device_set_wakeup_capable() be called in process context.
>> > >
>> > > I'm aware of that, but it's only happend in a handful of network drivers so far.
>> > >
>> > > I think this is a new case in -mm, though, isn't it?
>> >
>> > I'm not sure. ÂThe USB core does call device_set_wakeup_capable()
>> > while holding one or more spinlocks in usb_set_device_state(), and that
>> > routine is called in several places. ÂYou ought to be able to duplicate
>> > the error on your own system simply by plugging in a USB hub.
>>
>> No, I'm not. ÂAt least not with 2.6.37.
>>
>> Also, I think the problem would have been reported before if it had been that
>> easy to reproduce with the mainline kernel.
>
> Or do I need to enable a specific CONFIG_ option to reproduce it?
>
> Rafael
>

When I am googling, I found https://lkml.org/lkml/2011/1/14/440.
Maybe the bug is caused by that.
It is in linux-next and mmotm, not linus tree.



-- 
Kind regards,
Minchan Kim
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