From: Al Viro <viro@zeniv.linux.org.uk>
To: Christian Brauner <brauner@kernel.org>
Cc: linux-fsdevel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [RFC] move_mount(2): still breakage around new mount detection
Date: Tue, 29 Apr 2025 06:10:54 +0100 [thread overview]
Message-ID: <20250429051054.GP2023217@ZenIV> (raw)
In-Reply-To: <20250429040358.GO2023217@ZenIV>
On Tue, Apr 29, 2025 at 05:03:58AM +0100, Al Viro wrote:
> On Mon, Apr 28, 2025 at 07:53:18PM +0100, Al Viro wrote:
>
> > FWIW, I've a series of cleanups falling out of audit of struct mount
> > handling; it's still growing, but I'll post the stable parts for review
> > tonight or tomorrow...
>
> _Another_ fun one, this time around do_umount().
... and more, from 620c266f3949 "fhandle: relax open_by_handle_at()
permission checks" - just what is protecting has_locked_children()
use there? We are, after all, iterating through ->mnt_mounts -
with no locks whatsoever. Not to mention the fun question regarding
the result (including the bits sensitive to is_mounted()) remaining
valid by the time you get through exportfs_decode_fh_raw() (and no,
you can't hold any namespace_sem over it - no IO allowed under
that, so we'll need to recheck after that point)...
next prev parent reply other threads:[~2025-04-29 5:10 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-28 6:30 [RFC] move_mount(2): still breakage around new mount detection Al Viro
2025-04-28 7:03 ` Al Viro
2025-04-28 8:50 ` Christian Brauner
2025-04-28 18:53 ` Al Viro
2025-04-29 4:03 ` Al Viro
2025-04-29 5:10 ` Al Viro [this message]
2025-04-29 5:27 ` Al Viro
2025-04-29 8:21 ` Christian Brauner
2025-05-05 5:08 ` Al Viro
2025-05-05 14:20 ` Christian Brauner
2025-04-29 7:56 ` Christian Brauner
2025-04-29 12:27 ` Al Viro
2025-04-29 7:52 ` Christian Brauner
2025-05-08 5:56 ` more breakage there (was Re: [RFC] move_mount(2): still breakage around new mount detection) Al Viro
2025-05-08 19:59 ` Al Viro
2025-05-08 20:00 ` [PATCH 1/4] __legitimize_mnt(): check for MNT_SYNC_UMOUNT should be under mount_lock Al Viro
2025-05-09 11:02 ` Christian Brauner
2025-05-08 20:01 ` [PATCH 2/4] do_umount(): add missing barrier before refcount checks in sync case Al Viro
2025-05-09 11:02 ` Christian Brauner
2025-05-08 20:02 ` [PATCH 3/4] do_move_mount(): don't leak MNTNS_PROPAGATING on failures Al Viro
2025-05-08 20:03 ` reproducer for "do_move_mount(): don't leak MNTNS_PROPAGATING on failures" Al Viro
2025-05-09 11:02 ` [PATCH 3/4] do_move_mount(): don't leak MNTNS_PROPAGATING on failures Christian Brauner
2025-05-13 11:03 ` Lai, Yi
2025-05-13 12:08 ` Al Viro
2025-05-13 14:33 ` Lai, Yi
2025-05-08 20:02 ` [PATCH 4/4] fix IS_MNT_PROPAGATING uses Al Viro
2025-05-08 20:04 ` reproducer for "fix IS_MNT_PROPAGATING uses" Al Viro
2025-05-09 11:01 ` [PATCH 4/4] fix IS_MNT_PROPAGATING uses Christian Brauner
2025-05-09 11:06 ` more breakage there (was Re: [RFC] move_mount(2): still breakage around new mount detection) Christian Brauner
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