On 12/16/2012 07:23 PM, Tomas Winkler wrote:
> 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@xxxxxxxxx>
> Cc: Wanlong Gao <gaowanlong@xxxxxxxxxxxxxx>
> Signed-off-by: Jerry Snitselaar <jerry.snitselaar@xxxxxxxxxx>
> Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
Fixed the panic here, thank you.
Tested-by: Wanlong Gao <gaowanlong@xxxxxxxxxxxxxx>
> ---
> drivers/misc/mei/wd.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/misc/mei/wd.c b/drivers/misc/mei/wd.c
> index 636409f..9299a8c 100644
> --- a/drivers/misc/mei/wd.c
> +++ b/drivers/misc/mei/wd.c
> @@ -370,7 +370,7 @@ void mei_watchdog_register(struct mei_device *dev)
>
> void mei_watchdog_unregister(struct mei_device *dev)
> {
> - if (test_bit(WDOG_UNREGISTERED, &amt_wd_dev.status))
> + if (watchdog_get_drvdata(&amt_wd_dev) == NULL)
> return;
>
> watchdog_set_drvdata(&amt_wd_dev, NULL);
>
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