f2fs: Fix a system panic caused by f2fs_follow_link

In linux 3.10, we can not make sure the return value of nd_get_link function is valid. So this patch add a check before use it. Signed-off-by: Yunlei He <[email protected]> Signed-off-by: Shuoran Liu <[email protected]> Signed-off-by: Jaegeuk Kim <[email protected]>
kerneltoast · Apr 2, 2016 · b5a54be · b5a54be
1 parent e3f2622
commit b5a54be
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
@@ -318,13 +318,18 @@ static int f2fs_unlink(struct inode *dir, struct dentry *dentry)
 static void *f2fs_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
 	struct page *page;
+	char *link;
 
 	page = page_follow_link_light(dentry, nd);
 	if (IS_ERR(page))
 		return page;
 
+	link = nd_get_link(nd);
+	if (IS_ERR(link))
+		return link;
+
 	/* this is broken symlink case */
-	if (*nd_get_link(nd) == 0) {
+	if (*link == 0) {
 		kunmap(page);
 		page_cache_release(page);
 		return ERR_PTR(-ENOENT);