On Thu, Aug 21, 2025 at 03:27:26PM +0400, Askar Safin wrote:

man open_tree says:

quoted

mount propagation
(as described in
.BR mount_namespaces (7))
will not be applied to bind-mounts created by
.BR open_tree ()
until the bind-mount is attached with
.BR move_mount (2),

It seems this is wrong, because this commit exists: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=06b1ce966e3f8bfef261c111feb3d4b33ede0cd8 .
I'm not sure about this. (I didn't test this.)

No, it's correct. I reverted this because it broke userspace that relies
on this behavior.