--- sys/bus/cam/scsi/scsi_ch.c
+++ sys/bus/cam/scsi/scsi_ch.c
@@ -540,6 +540,10 @@
 		struct page_element_address_assignment *ea;
 		char announce_buf[80];
 
+		/* DF-5333: cherror() can return 0 for a completion that is not
+		 * CAM_REQ_CMP (SCSI INTERMED, RECOVERED ERROR sense) -- neither
+		 * branch below initializes announce_buf in that case. */
+		announce_buf[0] = '\0';
 
 		mode_header = (struct scsi_mode_header_6 *)csio->data_ptr;