commit d692170037c0338b31dac5ac4722c1360a4b5257
author Tomas Winkler <tomas.winkler@intel.com> Sun Dec 16 13:23:17 2012 +0200
committer Wim Van Sebroeck <wim@iguana.be> Wed Dec 19 22:25:11 2012 +0100
tree 0de83610a209aaefdb908292e79b875c0d865d6d
parent 8c4c419ca3bd5a5b3389114e037a9d17bdec3a5f

watchdog: mei: avoid oops in watchdog unregister code path

With commit c7d3df3 "mei: use internal watchdog device registration
tracking" will crash the kernel on shutdown path on systems
where ME watchdog is not present.
Since the watchdog was never initialized in such case
the WDOG_UNREGISTERED bit is never set and the system
crashes on access to uninitialized variables down the path.

To solve the issue we query for NULL on watchdog driver driver_data
to check whether the device is registered. This is handled in the
driver and doesn't depend on watchdog core internals.

Cc: Borislav Petkov <bp@alien8.de>
Cc: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Jerry Snitselaar <jerry.snitselaar@oracle.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>