From: Keith Busch <kbusch@kernel.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: io-uring@vger.kernel.org, asml.silence@gmail.com,
naup96721@gmail.com, stable@vger.kernel.org
Subject: Re: [PATCH 1/2] io_uring: ensure ctx->rings is stable for task work flags manipulation
Date: Wed, 11 Mar 2026 09:06:36 -0600 [thread overview]
Message-ID: <abGE_CLo4vW_-Tkh@kbusch-mbp> (raw)
In-Reply-To: <20260311131336.197028-2-axboe@kernel.dk>
On Wed, Mar 11, 2026 at 07:11:55AM -0600, Jens Axboe wrote:
> +/*
> + * Sets IORING_SQ_TASKRUN in the sq_flags shared with userspace, using the
> + * RCU protected rings pointer to be safe against concurrent ring resizing.
> + * Must be called inside an RCU read-side critical section.
You can make the rcu requirement explicit in the code with:
ASSERT(rcu_read_lock_held());
And debug kernels will catch misuse, too.
> + */
> +static void io_ctx_mark_taskrun(struct io_ring_ctx *ctx)
> +{
> + if (ctx->flags & IORING_SETUP_TASKRUN_FLAG) {
> + struct io_rings *rings = rcu_dereference(ctx->rings_rcu);
> +
> + atomic_or(IORING_SQ_TASKRUN, &rings->sq_flags);
> + }
> +}
next prev parent reply other threads:[~2026-03-11 15:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-11 13:11 [PATCHSET v2] Fix DEFER_TASKRUN ring resize flag manipulation Jens Axboe
2026-03-11 13:11 ` [PATCH 1/2] io_uring: ensure ctx->rings is stable for task work flags manipulation Jens Axboe
2026-03-11 15:06 ` Keith Busch [this message]
2026-03-11 15:12 ` Jens Axboe
2026-03-11 13:11 ` [PATCH 2/2] io_uring/eventfd: use ctx->rings_rcu for flags checking Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2026-03-10 14:45 [PATCHSET 0/2] Fix DEFER_TASKRUN ring resize flag manipulation Jens Axboe
2026-03-10 14:45 ` [PATCH 1/2] io_uring: ensure ctx->rings is stable for task work flags manipulation Jens Axboe
2026-03-11 11:13 ` Pavel Begunkov
2026-03-11 13:05 ` Jens Axboe
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