4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Tetsuo Handa <[email protected]> commit 543b8f8662fe6d21f19958b666ab0051af9db21a upstream. syzbot is reporting use-after-free at fuse_kill_sb_blk() [1]. Since sb->s_fs_info field is not cleared after fc was released by fuse_conn_put() when initialization failed, fuse_kill_sb_blk() finds already released fc and tries to hold the lock. Fix this by clearing sb->s_fs_info field after calling fuse_conn_put(). [1] https://syzkaller.appspot.com/bug?id=a07a680ed0a9290585ca424546860464dd9658db Signed-off-by: Tetsuo Handa <[email protected]> Reported-by: syzbot <[email protected]> Fixes: 3b463ae0c626 ("fuse: invalidation reverse calls") Cc: John Muir <[email protected]> Cc: Csaba Henk <[email protected]> Cc: Anand Avati <[email protected]> Cc: <[email protected]> # v2.6.31 Signed-off-by: Miklos Szeredi <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/fuse/inode.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1158,6 +1158,7 @@ static int fuse_fill_super(struct super_ err_put_conn: fuse_bdi_destroy(fc); fuse_conn_put(fc); + sb->s_fs_info = NULL; err_fput: fput(file); err:
