diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index e96a48b9e86c499c1c1732e83925789d78ddc508..3058b68b67404ec60e7f437492ebd45e97729d38 100644
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -2016,6 +2016,11 @@ static void NCR5380_reselect(struct Scsi_Host *instance)
 	NCR5380_write(MODE_REG, MR_BASE);
 
 	target_mask = NCR5380_read(CURRENT_SCSI_DATA_REG) & ~(hostdata->id_mask);
+	if (!target_mask || target_mask & (target_mask - 1)) {
+		shost_printk(KERN_WARNING, instance,
+			     "reselect: bad target_mask 0x%02x\n", target_mask);
+		return;
+	}
 
 	dsprintk(NDEBUG_RESELECTION, instance, "reselect\n");