--- b4ee28dec5218b19db9682e729458e4d6b30d2bb
+++ a158a6c925d07149fee6ca10f08e89ac65b0ed52
@@ -2497,8 +2497,11 @@ static void atapi_qc_complete(struct ata
 		 *
 		 * If door lock fails, always clear sdev->locked to
 		 * avoid this infinite loop.
+		 *
+		 * This may happen before SCSI scan is complete.  Make
+		 * sure qc->dev->sdev isn't NULL before dereferencing.
 		 */
-		if (qc->cdb[0] == ALLOW_MEDIUM_REMOVAL)
+		if (qc->cdb[0] == ALLOW_MEDIUM_REMOVAL && qc->dev->sdev)
 			qc->dev->sdev->locked = 0;
 
 		qc->scsicmd->result = SAM_STAT_CHECK_CONDITION;
@@ -2825,7 +2828,7 @@ static unsigned int ata_scsi_pass_thru(s
 	 * write indication (used for PIO/DMA setup), result TF is
 	 * copied back and we don't whine too much about its failure.
 	 */
-	tf->flags = ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
 	if (scmd->sc_data_direction == DMA_TO_DEVICE)
 		tf->flags |= ATA_TFLAG_WRITE;