From: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> commit 851e99ebeec3f4a672bb5010cf1ece095acee447 upstream. 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(). Link: https://lore.kernel.org/all/20220225165219.737025658@xxxxxxxxxxx/ Link: https://lkml.kernel.org/r/20220225153426.1c4cab6b@xxxxxxxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Acked-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Reported-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Fixes: 48b27b6b5191 ("tracefs: Set all files to the same group ownership as the mount option") Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/tracefs/inode.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -265,7 +265,6 @@ static int tracefs_parse_options(char *d 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)) @@ -292,7 +291,9 @@ static int tracefs_apply_options(struct inode->i_mode |= opts->mode; inode->i_uid = opts->uid; - inode->i_gid = opts->gid; + + /* Set all the group ids to the mount option */ + set_gid(sb->s_root, opts->gid); return 0; }
