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From: Bart Van Assche <bvanassche@acm.org>
To: Benjamin LaHaise <ben@communityfibre.ca>
Cc: Edward Adam Davis <eadavis@qq.com>,
	syzbot+b91eb2ed18f599dd3c31@syzkaller.appspotmail.com,
	brauner@kernel.org, jack@suse.cz, linux-aio@kvack.org,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk
Subject: Re: [PATCH] fs/aio: fix uaf in sys_io_cancel
Date: Mon, 4 Mar 2024 09:40:35 -0800	[thread overview]
Message-ID: <5ee4df86-458f-4544-85db-81dc82c2df4c@acm.org> (raw)
In-Reply-To: <20240304173120.GP20455@kvack.org>

On 3/4/24 09:31, Benjamin LaHaise wrote:
> A revert is justified when a series of patches is buggy and had
> insufficient review prior to merging.

That's not how Linux kernel development works. If a bug can get fixed
easily, a fix is preferred instead of reverting + reapplying a patch.

> Using the "a kernel warning hit" approach for work on cancellation is
> very much a sign that the patches were half baked.
Is there perhaps a misunderstanding? My patches fix a kernel warning and
did not introduce any new WARN*() statements.

> Why are you touching the kiocb after ownership has already been
> passed on to another entity?
Touching the kiocb after ownership has been passed is the result of an
oversight. Whether or not kiocb->ki_cancel() transfers ownership depends
on the I/O type. The use-after-free was not introduced on purpose.

Bart.


  reply	other threads:[~2024-03-04 17:40 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-03  7:29 [syzbot] [fs?] KASAN: slab-use-after-free Read in sys_io_cancel syzbot
2024-03-03 12:21 ` [PATCH] fs/aio: fix uaf " Edward Adam Davis
2024-03-04 16:15   ` Bart Van Assche
2024-03-04 17:03     ` Benjamin LaHaise
2024-03-04 17:15       ` Bart Van Assche
2024-03-04 17:31         ` Benjamin LaHaise
2024-03-04 17:40           ` Bart Van Assche [this message]
2024-03-04 17:47             ` Benjamin LaHaise
2024-03-04 17:58               ` Bart Van Assche
2024-03-04 18:02                 ` Benjamin LaHaise

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