[PATCH] scsi: sd: fix crashes in sd_resume_runtime

[Stanley Chu]

Hi Miles,

On Fri, 2021-10-15 at 15:46 +0800, Miles Chen wrote:
> After merging commit ed4246d37f3b ("scsi: sd: REQUEST SENSE for
> BLIST_IGN_MEDIA_CHANGE devices in runtime_resume()"), I hit the
> following crash on my device.
> 
> static int sd_resume_runtime(struct device *dev)
> {
>         struct scsi_disk *sdkp = dev_get_drvdata(dev);
>         struct scsi_device *sdp = sdkp->device; // sdkp == NULL and
> crash
> 
>         if (sdp->ignore_media_change) {
> 	...
> }
> 
> I checked sd_resume() and found that sdkp is possbile to be NULL, and
> there is a null pointer test in sd_resume() for this case.
> To fix this crash, follow sd_resume() to test if sdkp is NULL
> before dereferencing it.


LGTM.

Reviewed-by: Stanley Chu <stanley.chu at mediatek.com>