From: Jens Axboe <axboe@kernel.dk>
To: Fedor Pchelkin <pchelkin@ispras.ru>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
Alexey Khoroshilov <khoroshilov@ispras.ru>,
lvc-project@linuxtesting.org
Subject: Re: [PATCH 5.10/5.15] io_uring: avoid null-ptr-deref in io_arm_poll_handler
Date: Thu, 16 Mar 2023 12:58:46 -0600 [thread overview]
Message-ID: <23aa947b-43b6-d1d3-f8b4-4518cf4dcabb@kernel.dk> (raw)
In-Reply-To: <20230316185616.271024-1-pchelkin@ispras.ru>
On 3/16/23 12:56 PM, Fedor Pchelkin wrote:
> No upstream commit exists for this commit.
>
> The issue was introduced with backporting upstream commit c16bda37594f
> ("io_uring/poll: allow some retries for poll triggering spuriously").
>
> Memory allocation can possibly fail causing invalid pointer be
> dereferenced just before comparing it to NULL value.
>
> Move the pointer check in proper place (upstream has the similar location
> of the check). In case the request has REQ_F_POLLED flag up, apoll can't
> be NULL so no need to check there.
>
> Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Ah thanks, yes that's a mistake. Looks good to me!
--
Jens Axboe
next prev parent reply other threads:[~2023-03-16 18:58 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-16 18:56 Fedor Pchelkin
2023-03-16 18:58 ` Jens Axboe [this message]
2023-03-16 19:04 ` Greg Kroah-Hartman
2023-03-16 19:22 ` Fedor Pchelkin
2023-03-16 19:25 ` Jens Axboe
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