Re: kern/57552: fileassoc(9) causes rm to take kernel lock even when never used

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

> Date: Mon, 31 Jul 2023 01:00:02 +0000 (UTC)
> From: David Holland <dholland-bugs%netbsd.org@localhost>
>  
>  > (It's also not clear vp->v_mount is safe inside fileassoc_file_lookup.)
> 
> That one I don't follow. The mount shouldn't be able to go away while
> the caller is holding a vnode.

The vnode can change identity while the caller holds a reference, if
it is concurrently revoked.  Unless there's some non-obvious context
guaranteeing concurrent revoke can't happen, access to vp->v_mount
would race with that.