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/20220601062544.905141-2-damien.lemoal@opensource.wdc.com
Fixes: 89d947561077 ("sd: Implement support for ZBC devices")
Reported-by: Dongliang Mu <mudongliangabcd@gmail.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index a8f61b6ea479a7ac61a5b33175b77c8b70985297..856024c6852c4ccb44050582db65d79a6645d26a 100644 (file)
--- a/drivers/scsi/sd.c
+++ b/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);