Re: possible race between reset and error handling in usbhid

Am Donnerstag, 13. Oktober 2011, 18:20:52 schrieb Jiri Kosina:

On Wed, 12 Oct 2011, Oliver Neukum wrote:

quoted

looking at the usbhid code it seems to me that there is no protection
between the error handling code and pre_reset() racing.

In particular there seems to be no protection from hid_retry_timeout() calling
hid_start_in() which would start IO after hid_pre_reset() has already called
hid_cease_io() because that uses del_timer(), not del_timer_sync()

What do you think about this patch?

Looks like you made a good catch, thanks. Out of curiosity -- did you 
encounter this happening for real, or have you find out by code reading?

A bit of both. I was looking for causes of a mysterious bug report that
just mentions HID devices and resets and is known to be a race.
So I may have indirectly encountered it.

	Regards
		Oliver