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| author | Daniel Borkmann <daniel@iogearbox.net> | 2015-11-05 02:01:51 +0300 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2015-11-11 10:04:44 +0300 |
| commit | 0ee9608c89e81a1ccee52ecb58a7ff040e2522d9 (patch) | |
| tree | 97cf1ee6fd2d9e07839529c4fb2befc926ad93f7 /fs | |
| parent | ce5c2d2c256a4c8b523036537cd6be2d6af8f69d (diff) | |
| download | linux-0ee9608c89e81a1ccee52ecb58a7ff040e2522d9.tar.xz | |
debugfs: fix refcount imbalance in start_creating
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
review.
Fixes: 190afd81e4a5 ("debugfs: split the beginning and the end of __create_file() off")
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/debugfs/inode.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index 5d8f35f1382a..b7fcc0de0b2f 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -271,8 +271,12 @@ static struct dentry *start_creating(const char *name, struct dentry *parent) dput(dentry); dentry = ERR_PTR(-EEXIST); } - if (IS_ERR(dentry)) + + if (IS_ERR(dentry)) { mutex_unlock(&d_inode(parent)->i_mutex); + simple_release_fs(&debugfs_mount, &debugfs_mount_count); + } + return dentry; } |