From: "Steven Rostedt (Google)" rostedt@goodmis.org

Al Viro brought it to my attention that the dentries may not be filled when the parse_options() is called, causing the call to set_gid() to possibly crash. It should only be called if parse_options() succeeds totally anyway.

He suggested the logical place to do the update is in apply_options().

Cc: stable@vger.kernel.org Reported-by: Al Viro viro@zeniv.linux.org.uk Fixes: 48b27b6b5191 ("tracefs: Set all files to the same group ownership as the mount option") Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org --- fs/tracefs/inode.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index bafc02bf8220..3638d330ff5a 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -264,7 +264,6 @@ static int tracefs_parse_options(char *data, struct tracefs_mount_opts *opts) if (!gid_valid(gid)) return -EINVAL; opts->gid = gid; - set_gid(tracefs_mount->mnt_root, gid); break; case Opt_mode: if (match_octal(&args[0], &option)) @@ -293,6 +292,9 @@ static int tracefs_apply_options(struct super_block *sb) inode->i_uid = opts->uid; inode->i_gid = opts->gid;

+ if (tracefs_mount && tracefs_mount->mnt_root) + set_gid(tracefs_mount->mnt_root, opts->gid); + return 0; }