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authorDaniel Borkmann <daniel@iogearbox.net>2015-11-05 00:01:51 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-12-14 21:24:36 -0800
commit03ecddec2c94e41d31fc1e9b5545f6ba7ced9985 (patch)
tree1af07c930a7a438b40a7967dcbede7158a70b476
parent3c10560e50f845881cdecfbc22fea7939720ad38 (diff)
debugfs: fix refcount imbalance in start_creating
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 review. Fixes: 190afd81e4a5 ("debugfs: split the beginning and the end of __create_file() off") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/debugfs/inode.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 12756040ca20..8bec8f1e4b31 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -276,8 +276,12 @@ 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;
}