Messages in this thread | | | Date | Sat, 13 Feb 2010 12:46:11 -0500 (EST) | From | Alan Stern <> | Subject | Re: S2R resume crash in 2.6.33-rc7 - NULL pointer dereference in dev_get_drvdata() for usbhid |
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On Sat, 13 Feb 2010, Bruno [UTF-8] Prémont wrote:
> On Mon, 08 February 2010 Alan Stern <stern@rowland.harvard.edu> wrote: > > Clearly something is setting usbhid->intf to NULL. But I don't see > > any code that would do it. You may have to resort to putting > > printk() statements at various strategic places to find out where it > > happens. You could start with the beginnings and ends of hid_suspend, > > hid_resume, and hid_reset_resume. Maybe also usbhid_disconnect(), > > just in case. > > I did add a few printk()s and WARN_ON()s to get a better idea of > why/when usbhid->intf is NULL and it is already since probe time of the > second interface anounced by the USB keyboard (hid.debug=1):
...
> This lets me guess that hid_add_device() is doing something wrong > here when report parsing fails... (as that one is the only one which > could be doing the initialization of usbhid which does work for the > first interface announced by my keyboard)
I don't know about doing anything wrong... However it does appear that in this case the interface is registered on the HID bus but doesn't get bound to a driver. Jiri will know whether or not that's the desired outcome.
On the other hand, I don't think there would be anything wrong with moving the
usbhid->intf = intf; usbhid->ifnum = interface->desc.bInterfaceNumber;
lines from usbhid_start() to usbhid_probe(), just before the call to hid_add_device(). It should fix the bug, and those lines do belong in the probe routine. Jiri, any problems with doing this?
Alan Stern
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