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Wed, 11 Mar 2026 06:13:43 -0700 (PDT) From: Jens Axboe To: io-uring@vger.kernel.org Cc: asml.silence@gmail.com, naup96721@gmail.com, Jens Axboe , stable@vger.kernel.org Subject: [PATCH 2/2] io_uring/eventfd: use ctx->rings_rcu for flags checking Date: Wed, 11 Mar 2026 07:11:56 -0600 Message-ID: <20260311131336.197028-3-axboe@kernel.dk> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260311131336.197028-1-axboe@kernel.dk> References: <20260311131336.197028-1-axboe@kernel.dk> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Similarly to what commit e78f7b70e837 did for local task work additions, use ->rings_rcu under RCU rather than dereference ->rings directly. See that commit for more details. Cc: stable@vger.kernel.org Fixes: 79cfe9e59c2a ("io_uring/register: add IORING_REGISTER_RESIZE_RINGS") Signed-off-by: Jens Axboe --- io_uring/eventfd.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/io_uring/eventfd.c b/io_uring/eventfd.c index 78f8ab7db104..ab789e1ebe91 100644 --- a/io_uring/eventfd.c +++ b/io_uring/eventfd.c @@ -76,11 +76,15 @@ void io_eventfd_signal(struct io_ring_ctx *ctx, bool cqe_event) { bool skip = false; struct io_ev_fd *ev_fd; - - if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED) - return; + struct io_rings *rings; guard(rcu)(); + + rings = rcu_dereference(ctx->rings_rcu); + if (!rings) + return; + if (READ_ONCE(rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED) + return; ev_fd = rcu_dereference(ctx->io_ev_fd); /* * Check again if ev_fd exists in case an io_eventfd_unregister call -- 2.53.0