From 043bc81efbfc5580ecd9da76118722649205f30a Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Fri, 21 Feb 2025 14:13:02 +0100 Subject: [PATCH] fs: add assert for move_mount() After we've attached a detached mount tree the anonymous mount namespace must be empty. Add an assert and make this assumption explicit. Link: https://lore.kernel.org/r/20250221-brauner-open_tree-v1-3-dbcfcb98c676@kernel.org Signed-off-by: Christian Brauner --- fs/namespace.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index 8ca28737f4ee8..c9670a198b507 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3423,10 +3423,13 @@ static int do_move_mount(struct path *old_path, struct path *new_path, out: unlock_mount(mp); if (!err) { - if (attached) + if (attached) { mntput_no_expire(parent); - else + } else { + /* Make sure we notice when we leak mounts. */ + VFS_WARN_ON_ONCE(!mnt_ns_empty(ns)); free_mnt_ns(ns); + } } return err; } -- 2.47.2