diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 6ecf863..b177fd3 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -612,9 +612,9 @@
 	struct writeback_control wbc = {
 		.nr_to_write = LONG_MAX,
 		.sync_mode = WB_SYNC_ALL,
-		.range_start = vma->vm_pgoff * PAGE_SIZE,
+		.range_start = (loff_t)vma->vm_pgoff * PAGE_SIZE,
 		 /* absolute end, byte at end included */
-		.range_end = vma->vm_pgoff * PAGE_SIZE +
+		.range_end = (loff_t)vma->vm_pgoff * PAGE_SIZE +
 			(vma->vm_end - vma->vm_start - 1),
 	};
 
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index c0762a3..8f528e7 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -1023,7 +1023,7 @@
 
 	csocket = NULL;
 
-	if (addr == NULL)
+	if (!addr || !strlen(addr))
 		return -EINVAL;
 
 	if (strlen(addr) >= UNIX_PATH_MAX) {
diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
index bc8807d..f4fea28 100644
--- a/net/9p/trans_xen.c
+++ b/net/9p/trans_xen.c
@@ -451,13 +451,13 @@
 		char str[16];
 
 		BUILD_BUG_ON(XEN_9PFS_NUM_RINGS > 9);
-		sprintf(str, "ring-ref%u", i);
+		sprintf(str, "ring-ref%d", i);
 		ret = xenbus_printf(xbt, dev->nodename, str, "%d",
 				    priv->rings[i].ref);
 		if (ret)
 			goto error_xenbus;
 
-		sprintf(str, "event-channel-%u", i);
+		sprintf(str, "event-channel-%d", i);
 		ret = xenbus_printf(xbt, dev->nodename, str, "%u",
 				    priv->rings[i].evtchn);
 		if (ret)