Re: [PATCH] fs/namespace: correctly handle errors returned by grab_requested_mnt_ns

[Andrei Vagin]

On Mon, Nov 24, 2025 at 3:23 AM Mark Brown <broonie@xxxxxxxxxx> wrote:
>
> On Sun, Nov 23, 2025 at 07:15:16AM -0800, Andrei Vagin wrote:
> > On Sun, Nov 23, 2025 at 4:51 AM Mark Brown <broonie@xxxxxxxxxx> wrote:
>
> > > listmount04.c:128: TFAIL: invalid mnt_id_req.spare expected EINVAL: EBADF (9)
>
> > The merged patch is slightly different from what you can see on the
> > mailing list, so it's better to look at commit 78f0e33cd6c93
> > ("fs/namespace: correctly handle errors returned by
> > grab_requested_mnt_ns") to understand what is going on here.
>
> > With this patch, the spare field can be used as the `mnt_ns_fd`. EINVAL
> > is returned if both mnt_ns_fd and mnt_ns_id are set. A non-zero
> > mnt_ns_fd (the old spare) is interpreted as a namespace file descriptor.
>
> I can see what's happening - the question is if the test failure it
> triggers is a problem in the kernel or in the test.

This is a test problem. The test has to be modified to check cases when
the target mount namespace is specified by mnt_fs_fd.

Thanks,
Andrei