[lkml]   [2015]   [Dec]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH 4.2 55/61] debugfs: fix refcount imbalance in start_creating
4.2-stable review patch.  If anyone has any objections, please let me know.


From: Daniel Borkmann <>

commit 0ee9608c89e81a1ccee52ecb58a7ff040e2522d9 upstream.

In debugfs' start_creating(), we pin the file system to safely access
its root. When we failed to create a file, we unpin the file system via
failed_creating() to release the mount count and eventually the reference
of the vfsmount.

However, when we run into an error during lookup_one_len() when still
in start_creating(), we only release the parent's mutex but not so the
reference on the mount. Looks like it was done in the past, but after
splitting portions of __create_file() into start_creating() and
end_creating() via 190afd81e4a5 ("debugfs: split the beginning and the
end of __create_file() off"), this seemed missed. Noticed during code

Fixes: 190afd81e4a5 ("debugfs: split the beginning and the end of __create_file() off")
Signed-off-by: Daniel Borkmann <>
Signed-off-by: Al Viro <>
Signed-off-by: Greg Kroah-Hartman <>

fs/debugfs/inode.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -271,8 +271,12 @@ static struct dentry *start_creating(con
dentry = ERR_PTR(-EEXIST);
- if (IS_ERR(dentry))
+ if (IS_ERR(dentry)) {
+ simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+ }
return dentry;

 \ /
  Last update: 2015-12-12 22:01    [W:0.350 / U:3.976 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site