scsi: sd: Fix potential NULL pointer dereference

If sd_probe() sees an early error before sdkp->device is initialized,
sd_zbc_release_disk() is called. This causes a NULL pointer dereference
when sd_is_zoned() is called inside that function. Avoid this by removing
the call to sd_zbc_release_disk() in sd_probe() error path.

This change is safe and does not result in zone information memory leakage
because the zone information for a zoned disk is allocated only when
sd_revalidate_disk() is called, at which point sdkp->disk_dev is fully set,
resulting in sd_disk_release() being called when needed to cleanup a disk
zone information using sd_zbc_release_disk().

Link: https://lore.kernel.org/r/[email protected]
Fixes: 89d9475 ("sd: Implement support for ZBC devices")
Reported-by: Dongliang Mu <[email protected]>
Suggested-by: Christoph Hellwig <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Damien Le Moal <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

Author: Damien Le Moal

drivers/scsi/sd.c

@@ -3544,7 +3544,6 @@ static int sd_probe(struct device *dev)
  out_put:
 	put_disk(gd);
  out_free:
-	sd_zbc_release_disk(sdkp);
 	kfree(sdkp);
  out:
 	scsi_autopm_put_device(sdp);