Re: f2fs: avoid abnormal behavior on broken symlink

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Jaegeuk Kim,

The patch feb7cbb079e6: "f2fs: avoid abnormal behavior on broken
symlink" from Apr 15, 2015, leads to the following static checker
warning:

	fs/f2fs/namei.c:304 f2fs_follow_link()
	warn: 'page' isn't an ERR_PTR

fs/f2fs/namei.c
   299  static void *f2fs_follow_link(struct dentry *dentry, struct nameidata *nd)
   300  {
   301          struct page *page;
   302  
   303          page = page_follow_link_light(dentry, nd);
   304          if (IS_ERR(page))
                           ^^^^
The code in page_follow_link_light() is a bit hard to follow but it
returns NULL on error.

   305                  return page;
   306  
   307          /* this is broken symlink case */
   308          if (*nd_get_link(nd) == 0) {
   309                  kunmap(page);
                        ^^^^^^^^^^^^
Potential NULL deref.

   310                  page_cache_release(page);
   311                  return ERR_PTR(-ENOENT);
   312          }
   313          return page;
   314  }

regards,
dan carpenter

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