From: Jens Axboe <axboe@kernel.dk>
To: Kyle Zeng <kylebot@openai.com>, io-uring@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, outbounddisclosures@openai.com
Subject: Re: [PATCH] io_uring/io-wq: save worker type before dropping its reference
Date: Fri, 30 Oct 2026 07:07:25 -0600 [thread overview]
Message-ID: <61bb0fc9-d629-4987-ad18-c5eb46074dbf@kernel.dk> (raw)
In-Reply-To: <20261030042101.73491-1-kylebot@openai.com>
On 10/29/26 10:21 PM, Kyle Zeng wrote:
> io_wq_cancel_tw_create() inspects cb->func after calling
> io_worker_cancel_cb(). For an existing worker, that call can drop the
> last worker reference and wake io_worker_exit(). If the canceling task
> is preempted, the worker can be unlinked and freed by kfree_rcu() before
> the callback function is inspected. KASAN reports a slab-use-after-free
> read in this path.
>
> Save whether the callback belongs to an unpublished continuation worker
> while its reference is still held, then use the saved result for the
> conditional free. This preserves the existing accounting and frees only
> the worker allocated for the canceled continuation.
This is already posted and queued up:
https://lore.kernel.org/io-uring/20261028164732.1264069-10-axboe@kernel.dk/T/#u
--
Jens Axboe
prev parent reply other threads:[~2026-10-30 13:07 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-30 4:21 [PATCH] io_uring/io-wq: save worker type before dropping its reference Kyle Zeng
2026-10-30 13:07 ` Jens Axboe [this message]
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