Index: head/sys/cam/cam_xpt.c
===================================================================
--- head/sys/cam/cam_xpt.c
+++ head/sys/cam/cam_xpt.c
@@ -435,6 +435,9 @@
 			inccb->csio.bio = NULL;
 #endif
 
+		if (inccb->ccb_h.flags & CAM_UNLOCKED)
+			return (EINVAL);
+
 		bus = xpt_find_bus(inccb->ccb_h.path_id);
 		if (bus == NULL)
 			return (EINVAL);
Index: head/sys/cam/scsi/scsi_pass.c
===================================================================
--- head/sys/cam/scsi/scsi_pass.c
+++ head/sys/cam/scsi/scsi_pass.c
@@ -1782,6 +1782,11 @@
 			inccb->csio.bio = NULL;
 #endif
 
+		if (inccb->ccb_h.flags & CAM_UNLOCKED) {
+			error = EINVAL;
+			break;
+		}
+
 		/*
 		 * Some CCB types, like scan bus and scan lun can only go
 		 * through the transport layer device.
@@ -1875,24 +1880,27 @@
 			xpt_print(periph->path, "Copy of user CCB %p to "
 				  "kernel address %p failed with error %d\n",
 				  *user_ccb, ccb, error);
-			uma_zfree(softc->pass_zone, io_req);
-			cam_periph_lock(periph);
-			break;
+			goto camioqueue_error;
 		}
 #if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING)
 		if (ccb->ccb_h.func_code == XPT_SCSI_IO)
 			ccb->csio.bio = NULL;
 #endif
 
+		if (ccb->ccb_h.flags & CAM_UNLOCKED) {
+			error = EINVAL;
+			goto camioqueue_error;
+		}
+
 		if (ccb->ccb_h.flags & CAM_CDB_POINTER) {
 			if (ccb->csio.cdb_len > IOCDBLEN) {
 				error = EINVAL;
-				break;
+				goto camioqueue_error;
 			}
 			error = copyin(ccb->csio.cdb_io.cdb_ptr,
 			    ccb->csio.cdb_io.cdb_bytes, ccb->csio.cdb_len);
-			if (error)
-				break;
+			if (error != 0)
+				goto camioqueue_error;
 			ccb->ccb_h.flags &= ~CAM_CDB_POINTER;
 		}
 
@@ -1904,10 +1912,8 @@
 			xpt_print(periph->path, "CCB function code %#x is "
 			    "restricted to the XPT device\n",
 			    ccb->ccb_h.func_code);
-			uma_zfree(softc->pass_zone, io_req);
-			cam_periph_lock(periph);
 			error = ENODEV;
-			break;
+			goto camioqueue_error;
 		}
 
 		/*
@@ -1953,11 +1959,8 @@
 		 || (fc == XPT_SMP_IO) || (fc == XPT_DEV_MATCH)
 		 || (fc == XPT_DEV_ADVINFO)) {
 			error = passmemsetup(periph, io_req);
-			if (error != 0) {
-				uma_zfree(softc->pass_zone, io_req);
-				cam_periph_lock(periph);
-				break;
-			}
+			if (error != 0)
+				goto camioqueue_error;
 		} else
 			io_req->mapinfo.num_bufs_used = 0;
 
@@ -2002,6 +2005,11 @@
 			TAILQ_INSERT_TAIL(&softc->done_queue, io_req, links);
 		}
 		break;
+
+camioqueue_error:
+		uma_zfree(softc->pass_zone, io_req);
+		cam_periph_lock(periph);
+		break;
 	}
 	case CAMIOGET:
 	{