Re: [btrfs?] general protection fault in getname_kernel (2)

[Edward Adam Davis]

The origin fc's source is NULL

#syz test

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 692f81f1e23e..06bdf0cf7b88 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -2148,6 +2148,8 @@ static int btrfs_dup_fs_context(struct fs_context *fc, struct fs_context *src_fc
 	 * mounting, and then once we free the dup it'll free ->source, so we
 	 * need to make sure we're only pointing to it in one fc.
 	 */
+	if (!src_fc->source)
+		return -EINVAL;
 	refcount_inc(&ctx->refs);
 	fc->fs_private = ctx;
 	fc->source = src_fc->source;