Alejandro Colomar [off-list ref] writes:

Hi Alyssa,

On Sat, Dec 13, 2025 at 06:58:53PM +0100, Alyssa Ross wrote:

quoted

I was surprised to discover than an O_PATH file descriptor was
insufficient.

How did you discover it?  Could you please link to relevant information
(or kernel sources)?

By trying it!

Presumably it's the fd_empty() check at the beginning of the syscall
implementation in nsproxy.c.

quoted

Since the mode of nsfs files is always 0444, tell
callers to always a file descriptor opened for reading.

Missing 'use'?

Yes.  Feel free to add it.