From: Al Viro <viro@zeniv.linux.org.uk>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Ian Kent <raven@themaw.net>, David Howells <dhowells@redhat.com>,
Christian Brauner <christian.brauner@ubuntu.com>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
Steven Whitehouse <swhiteho@redhat.com>,
Miklos Szeredi <mszeredi@redhat.com>,
Christian Brauner <christian@brauner.io>,
Jann Horn <jannh@google.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Linux API <linux-api@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
lkml <linux-kernel@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH 00/17] VFS: Filesystem information and notifications [ver #17]
Date: Fri, 6 Mar 2020 19:58:23 +0000 [thread overview]
Message-ID: <20200306195823.GZ23230@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20200306194322.GY23230@ZenIV.linux.org.uk>
On Fri, Mar 06, 2020 at 07:43:22PM +0000, Al Viro wrote:
> On Fri, Mar 06, 2020 at 05:25:49PM +0100, Miklos Szeredi wrote:
> > On Tue, Mar 03, 2020 at 08:46:09AM +0100, Miklos Szeredi wrote:
> > >
> > > I'm doing a patch. Let's see how it fares in the face of all these
> > > preconceptions.
> >
> > Here's a first cut. Doesn't yet have superblock info, just mount info.
> > Probably has rough edges, but appears to work.
>
> For starters, you have just made namespace_sem held over copy_to_user().
> This is not going to fly.
In case if the above is too terse: you grab your mutex while under
namespace_sem (see attach_recursive_mnt()); the same mutex is held
while calling dir_emit(). Which can (and normally does) copy data
to userland-supplied buffer.
NAK for that reason alone, and to be honest I had been too busy
suppressing the gag reflex to read and comment any deeper.
I really hate that approach, in case it's not clear from the above.
To the degree that I don't trust myself to filter out the obscenities
if I try to comment on it right now.
The only blocking thing we can afford under namespace_sem is GFP_KERNEL
allocation.
next prev parent reply other threads:[~2020-03-06 19:58 UTC|newest]
Thread overview: 117+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-21 18:01 [PATCH 00/17] VFS: Filesystem information and notifications [ver #17] David Howells
2020-02-21 18:01 ` [PATCH 01/17] watch_queue: Add security hooks to rule on setting mount and sb watches " David Howells
2020-02-21 18:02 ` [PATCH 02/17] watch_queue: Implement mount topology and attribute change notifications " David Howells
2020-02-21 18:02 ` [PATCH 03/17] watch_queue: sample: Display mount tree " David Howells
2020-02-21 18:02 ` [PATCH 04/17] watch_queue: Introduce a non-repeating system-unique superblock ID " David Howells
2020-02-21 18:02 ` [PATCH 05/17] watch_queue: Add superblock notifications " David Howells
2020-02-21 18:02 ` [PATCH 06/17] watch_queue: sample: Display " David Howells
2020-02-21 18:02 ` [PATCH 07/17] fsinfo: Add fsinfo() syscall to query filesystem information " David Howells
2020-02-26 2:29 ` Aleksa Sarai
2020-02-28 14:44 ` David Howells
2020-02-21 18:02 ` [PATCH 08/17] fsinfo: Provide a bitmap of supported features " David Howells
2020-02-21 18:03 ` [PATCH 09/17] fsinfo: Allow fsinfo() to look up a mount object by ID " David Howells
2020-02-21 18:03 ` [PATCH 10/17] fsinfo: Allow mount information to be queried " David Howells
2020-03-04 14:58 ` Miklos Szeredi
2020-03-04 16:10 ` Miklos Szeredi
2020-02-21 18:03 ` [PATCH 11/17] fsinfo: sample: Mount listing program " David Howells
2020-02-21 18:03 ` [PATCH 12/17] fsinfo: Allow the mount topology propogation flags to be retrieved " David Howells
2020-02-21 18:03 ` [PATCH 13/17] fsinfo: Query superblock unique ID and notification counter " David Howells
2020-02-21 18:03 ` [PATCH 14/17] fsinfo: Add API documentation " David Howells
2020-02-21 18:03 ` [PATCH 15/17] fsinfo: Add support for AFS " David Howells
2020-02-21 18:03 ` [PATCH 16/17] fsinfo: Add example support for Ext4 " David Howells
2020-02-21 18:04 ` [PATCH 17/17] fsinfo: Add example support for NFS " David Howells
2020-02-21 20:21 ` [PATCH 00/17] VFS: Filesystem information and notifications " James Bottomley
2020-02-24 10:24 ` Miklos Szeredi
2020-02-24 14:55 ` James Bottomley
2020-02-24 15:28 ` Miklos Szeredi
2020-02-25 12:13 ` Steven Whitehouse
2020-02-25 15:28 ` James Bottomley
2020-02-25 15:47 ` Steven Whitehouse
2020-02-26 9:11 ` Miklos Szeredi
2020-02-26 10:51 ` Steven Whitehouse
2020-02-27 5:06 ` Ian Kent
2020-02-27 9:36 ` Miklos Szeredi
2020-02-27 11:34 ` Ian Kent
2020-02-27 13:45 ` Miklos Szeredi
2020-02-27 15:14 ` Karel Zak
2020-02-28 0:43 ` Ian Kent
2020-02-28 8:35 ` Miklos Szeredi
2020-02-28 12:27 ` Greg Kroah-Hartman
2020-02-28 16:24 ` Miklos Szeredi
2020-02-28 17:15 ` Al Viro
2020-03-02 8:43 ` Miklos Szeredi
2020-03-02 10:34 ` Karel Zak
2020-02-28 16:42 ` David Howells
2020-02-28 15:08 ` James Bottomley
2020-02-28 15:40 ` Miklos Szeredi
2020-02-28 0:12 ` Ian Kent
2020-02-28 15:52 ` Christian Brauner
2020-02-28 16:36 ` David Howells
2020-03-02 9:09 ` Miklos Szeredi
2020-03-02 9:38 ` Greg Kroah-Hartman
2020-03-03 5:27 ` Ian Kent
2020-03-03 7:46 ` Miklos Szeredi
2020-03-06 16:25 ` Miklos Szeredi
2020-03-06 19:43 ` Al Viro
2020-03-06 19:54 ` Miklos Szeredi
2020-03-06 19:58 ` Al Viro [this message]
2020-03-06 20:05 ` Al Viro
2020-03-06 20:11 ` Miklos Szeredi
2020-03-06 20:37 ` Al Viro
2020-03-06 20:38 ` Al Viro
2020-03-06 20:45 ` Al Viro
2020-03-06 20:49 ` Al Viro
2020-03-06 20:51 ` Miklos Szeredi
2020-03-06 21:28 ` Al Viro
2020-03-06 20:56 ` Al Viro
2020-03-06 20:51 ` Miklos Szeredi
2020-03-07 9:48 ` Greg Kroah-Hartman
2020-03-07 20:48 ` Miklos Szeredi
2020-03-03 9:12 ` David Howells
2020-03-03 9:26 ` Miklos Szeredi
2020-03-03 9:48 ` Miklos Szeredi
2020-03-03 10:21 ` Steven Whitehouse
2020-03-03 10:32 ` Miklos Szeredi
2020-03-03 11:09 ` Ian Kent
2020-03-03 10:00 ` Christian Brauner
2020-03-03 10:13 ` Miklos Szeredi
2020-03-03 10:25 ` Christian Brauner
2020-03-03 11:33 ` Miklos Szeredi
2020-03-03 11:56 ` Christian Brauner
2020-03-03 11:38 ` Karel Zak
2020-03-03 13:03 ` Greg Kroah-Hartman
2020-03-03 13:14 ` Greg Kroah-Hartman
2020-03-03 13:34 ` Miklos Szeredi
2020-03-03 13:43 ` Greg Kroah-Hartman
2020-03-03 14:10 ` Greg Kroah-Hartman
2020-03-03 14:13 ` Jann Horn
2020-03-03 14:24 ` Greg Kroah-Hartman
2020-03-03 15:44 ` Jens Axboe
2020-03-03 16:37 ` Greg Kroah-Hartman
2020-03-03 16:51 ` Jeff Layton
2020-03-03 16:55 ` Jens Axboe
2020-03-03 19:02 ` Jeff Layton
2020-03-03 19:07 ` Jens Axboe
2020-03-03 19:23 ` Jens Axboe
2020-03-03 19:43 ` Jeff Layton
2020-03-03 20:33 ` Jens Axboe
2020-03-03 21:03 ` Jeff Layton
2020-03-03 21:20 ` Jens Axboe
2020-03-03 14:10 ` Miklos Szeredi
2020-03-03 14:29 ` Greg Kroah-Hartman
2020-03-03 14:40 ` Jann Horn
2020-03-03 16:51 ` Greg Kroah-Hartman
2020-03-03 16:57 ` Jann Horn
2020-03-03 20:15 ` Greg Kroah-Hartman
2020-03-03 14:40 ` David Howells
2020-03-04 4:20 ` Ian Kent
2020-03-03 14:19 ` David Howells
2020-03-03 16:59 ` Greg Kroah-Hartman
2020-03-03 14:23 ` Christian Brauner
2020-03-03 15:23 ` Greg Kroah-Hartman
2020-03-03 15:53 ` David Howells
2020-03-04 2:01 ` Ian Kent
2020-03-04 15:22 ` Karel Zak
2020-03-04 16:49 ` Greg Kroah-Hartman
2020-03-04 17:55 ` Karel Zak
2020-03-03 14:09 ` David Howells
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