From: Al Viro <viro@zeniv.linux.org.uk>
To: Christian Brauner <brauner@kernel.org>
Cc: linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH][RFC] ->mnt_devname is never NULL
Date: Mon, 21 Apr 2025 18:03:19 +0100 [thread overview]
Message-ID: <20250421170319.GX2023217@ZenIV> (raw)
In-Reply-To: <20250421162947.GW2023217@ZenIV>
On Mon, Apr 21, 2025 at 05:29:47PM +0100, Al Viro wrote:
> What's to prevent the 'beneath' case from getting mnt mount --move'd
> away *AND* the ex-parent from getting unmounted while we are blocked
> in inode_lock? At this point we are not holding any locks whatsoever
> (and all mount-related locks nest inside inode_lock(), so we couldn't
> hold them there anyway).
>
> Hit that race and watch a very unhappy umount...
While we are at it, in normal case inode_unlock() in unlock_mount()
is safe since we have dentry (and associated mount) pinned by
struct path we'd fed to matching lock_mount(). No longer true for
the 'beneath' case, AFAICS...
next prev parent reply other threads:[~2025-04-21 17:03 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-21 3:35 [PATCH][RFC] ->mnt_devname is never NULL Al Viro
2025-04-21 7:56 ` Christian Brauner
2025-04-21 16:29 ` Al Viro
2025-04-21 17:03 ` Al Viro [this message]
2025-04-22 3:14 ` [PATCH][RFC] do_lock_mount() races in 'beneath' case Al Viro
2025-04-22 7:47 ` Christian Brauner
2025-04-22 7:43 ` [PATCH][RFC] ->mnt_devname is never NULL Christian Brauner
2025-04-22 7:31 ` Christian Brauner
2025-04-22 12:25 ` Al Viro
2025-04-22 13:40 ` Christian Brauner
2025-04-23 1:30 ` Al Viro
2025-04-23 22:20 ` Al Viro
2025-04-24 8:56 ` Christian Brauner
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