From: Jens Axboe <axboe@kernel.dk>
To: Ian Abbott <abbotti@mev.co.uk>
Cc: syzbot <syzbot+01523a0ae5600aef5895@syzkaller.appspotmail.com>,
io-uring@vger.kernel.org, linux-kernel@vger.kernel.org,
syzkaller-bugs@googlegroups.com, hsweeten@visionengravers.com,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [syzbot] [io-uring?] KASAN: slab-use-after-free Read in io_poll_remove_entries
Date: Tue, 22 Jul 2025 07:53:55 -0600 [thread overview]
Message-ID: <8320bd2b-b6d2-4ed8-84c6-cb04999e9f53@kernel.dk> (raw)
In-Reply-To: <20250722134724.6671e45b@ian-deb>
> Thanks for your investigation and initial fix. I think dev->attach_lock
> needs to be write-locked before calling is_device_busy() and released
> after comedi_device_detach() (although that also write-locks it, so we
> need to refactor that). Otherwise, someone could get added to the
> wait_head after is_device_busy() returns.
Looked at this one post coffee, and this looks good to me. If the
->cancel() part is all fine with attach_lock being held, this looks like
the simplest solution to the issue.
I still think the whole busy notion etc needs rethinking in comedi, it
should follow a more idiomatic approach rather than be special. But
that's really separate from this fix.
--
Jens Axboe
next prev parent reply other threads:[~2025-07-22 13:53 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-19 17:29 [syzbot] [io-uring?] KASAN: slab-use-after-free Read in io_poll_remove_entries syzbot
2025-07-20 0:36 ` Hillf Danton
2025-07-20 0:49 ` syzbot
2025-07-20 18:24 ` Jens Axboe
2025-07-20 18:49 ` Jens Axboe
2025-07-20 19:00 ` Jens Axboe
2025-07-20 19:19 ` [syzbot] [kernel] " syzbot
2025-07-22 12:21 ` [syzbot] [io-uring?] " Jens Axboe
2025-07-22 12:30 ` Ian Abbott
2025-07-22 12:43 ` Jens Axboe
2025-07-22 12:31 ` Greg Kroah-Hartman
2025-07-22 12:44 ` Jens Axboe
2025-07-22 12:47 ` Ian Abbott
2025-07-22 13:00 ` Jens Axboe
2025-07-22 13:07 ` Ian Abbott
2025-07-22 13:31 ` Ian Abbott
2025-07-22 13:50 ` Jens Axboe
2025-07-22 14:03 ` Ian Abbott
2025-07-22 13:53 ` Jens Axboe [this message]
2025-07-22 14:15 ` Ian Abbott
2025-07-23 14:08 ` Aleksandr Nogikh
2025-07-22 12:47 ` Jens Axboe
2025-07-22 13:14 ` [syzbot] [kernel] " syzbot
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