On Tue, Nov 16, 2021 at 12:16:30AM +0200, Mathias Nyman wrote: > xHC hardware can only have one slot in default state with address 0 > waiting for a unique address at a time, otherwise "undefined behavior > may occur" according to xhci spec 5.4.3.4 > > The address0_mutex exists to prevent this across both xhci roothubs. > > If hub_port_init() fails, it may unlock the mutex and exit with a xhci > slot in default state. If the other xhci roothub calls hub_port_init() > at this point we end up with two slots in default state. > > Make sure the address0_mutex protects the slot default state across > hub_port_init() retries, until slot is addressed or disabled. > > Note, one known minor case is not fixed by this patch. > If device needs to be reset during resume, but fails all hub_port_init() > retries in usb_reset_and_verify_device(), then it's possible the slot is > still left in default state when address0_mutex is unlocked. > > Cc: <stable@xxxxxxxxxxxxxxx> > Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> What commit id does this "fix"? thanks, greg k-h
