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| author | Daniel Borkmann <daniel@iogearbox.net> | 2015-11-04 23:33:17 +0100 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2015-11-04 22:13:45 -0500 |
| commit | d227c3ae4e94e5eb11dd780a811f59e1a7b74ccd (patch) | |
| tree | 1335f64815650b7f1cf7ec457e3453a78bc88a77 | |
| parent | 43ed384339ae67a74a8ba4851268b23216ef7a44 (diff) | |
| download | linux-d227c3ae4e94e5eb11dd780a811f59e1a7b74ccd.tar.gz linux-d227c3ae4e94e5eb11dd780a811f59e1a7b74ccd.tar.bz2 linux-d227c3ae4e94e5eb11dd780a811f59e1a7b74ccd.zip | |
tracefs: Fix refcount imbalance in start_creating()
In tracefs' 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 singleton 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.
F.e., in securityfs_create_file(), after doing simple_pin_fs() when
lookup_one_len() fails there, we infact do simple_release_fs(). This
seems necessary here as well.
Same issue seen in debugfs due to 190afd81e4a5 ("debugfs: split the
beginning and the end of __create_file() off"), which seemed to got
carried over into tracefs, too. Noticed during code review.
Link: http://lkml.kernel.org/r/68efa86101b778cf7517ed7c6ad573bd69f60ec6.1446672850.git.daniel@iogearbox.net
Fixes: 4282d60689d4 ("tracefs: Add new tracefs file system")
Cc: stable@vger.kernel.org # 4.1+
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| -rw-r--r-- | fs/tracefs/inode.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index cbc8d5d2755a..c66f2423e1f5 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -340,8 +340,12 @@ 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(&parent->d_inode->i_mutex); + simple_release_fs(&tracefs_mount, &tracefs_mount_count); + } + return dentry; } |