A temperature conversion can take 750 ms and when possible the
w1_therm slave driver drops the bus_mutex to allow other bus
operations, but that includes operations such as a periodic slave
search, which can remove this slave when it is no longer detected.
If that happens the sl->family_data will be freed and set to NULL
causing w1_slave_show to crash when it wakes up.
Signed-off-by: NDavid Fries <David@Fries.net>
Reported-By: NThorsten Bschorr <thorsten@bschorr.de>
Tested-by: NThorsten Bschorr <thorsten@bschorr.de>
Acked-by: NEvgeniy Polyakov <zbr@ioremap.net>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>