lkml.org 
[lkml]   [2011]   [Feb]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [BUG] usb_set_device_state
Date
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. Rafael, 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. The 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. You ought to be able to duplicate
> > the error on your own system simply by plugging in a USB hub.
>
> No, I'm not. At 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


\
 
 \ /
  Last update: 2011-02-06 13:05    [W:0.046 / U:0.584 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site