From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6729619FA93; Wed, 25 Feb 2026 01:42:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771983744; cv=none; b=ECY6ZbFuuj+O/lbEg7wUMJU2sQSgKrwx9iNDfWGNAsgbp3VLfxEt8o5pLB/B/i5B5XWMzZrksfajx0m5qa1f4Nu+80267UkkHDbgalXd/Z+IdZQQt3CXGtaXjTNQw9FK9EtyIl4aAFrX5QgCdD6mbymp49DBrZXKYDkfHJ6GhVw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771983744; c=relaxed/simple; bh=PtZbwm77/yUuVOgdgM2mJwVC7pcmgKbOwsgM+SL2X/E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EWcJAFpAckTKW/QNGUOUrmFMjFnVoW11CgYHSI4cZd8PfURd758vs1h9yzyNJLLjhF/uwfqYWnMXBvQRP1iQYVg7+1jg1TtKQDiaOMaSmlj5rlCRlDGUAjA8fYF7/+NmzEtleevPGgQwTm4nPzFTIQTlDlbIQzj3UP/UJUu2j18= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=vl3bAjo+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="vl3bAjo+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D876C116D0; Wed, 25 Feb 2026 01:42:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1771983744; bh=PtZbwm77/yUuVOgdgM2mJwVC7pcmgKbOwsgM+SL2X/E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vl3bAjo+fah5wz5V5tqq8OdWp2AqhN83V16l1AfPtQeZrT0ntWK2EOAO+nVHNuILc zS0UICBff9oKAHSBphmo3RYIJ3Q6XJ1caJS5a02pC4TRJerccPmQtzSJvPc78096JC Ry3cVZ3zG7dS/IVink+nGBNTjpGKMl91VJ1S3UKY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Caleb Sander Mateos , Joanne Koong , Gabriel Krisman Bertazi , Jens Axboe , Sasha Levin Subject: [PATCH 6.18 037/641] io_uring: use release-acquire ordering for IORING_SETUP_R_DISABLED Date: Tue, 24 Feb 2026 17:16:03 -0800 Message-ID: <20260225012349.901111466@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260225012348.915798704@linuxfoundation.org> References: <20260225012348.915798704@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Caleb Sander Mateos [ Upstream commit 7a8737e1132ff07ca225aa7a4008f87319b5b1ca ] io_uring_enter(), __io_msg_ring_data(), and io_msg_send_fd() read ctx->flags and ctx->submitter_task without holding the ctx's uring_lock. This means they may race with the assignment to ctx->submitter_task and the clearing of IORING_SETUP_R_DISABLED from ctx->flags in io_register_enable_rings(). Ensure the correct ordering of the ctx->flags and ctx->submitter_task memory accesses by storing to ctx->flags using release ordering and loading it using acquire ordering. Signed-off-by: Caleb Sander Mateos Fixes: 4add705e4eeb ("io_uring: remove io_register_submitter") Reviewed-by: Joanne Koong Reviewed-by: Gabriel Krisman Bertazi Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- io_uring/io_uring.c | 6 +++++- io_uring/msg_ring.c | 12 ++++++++++-- io_uring/register.c | 3 ++- 3 files changed, 17 insertions(+), 4 deletions(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 104192bcc8e4b..d8a35a49dd1ac 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -3490,7 +3490,11 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, ctx = file->private_data; ret = -EBADFD; - if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED)) + /* + * Keep IORING_SETUP_R_DISABLED check before submitter_task load + * in io_uring_add_tctx_node() -> __io_uring_add_tctx_node_from_submit() + */ + if (unlikely(smp_load_acquire(&ctx->flags) & IORING_SETUP_R_DISABLED)) goto out; /* diff --git a/io_uring/msg_ring.c b/io_uring/msg_ring.c index 5e5b94236d720..bce74a8b64c6e 100644 --- a/io_uring/msg_ring.c +++ b/io_uring/msg_ring.c @@ -124,7 +124,11 @@ static int __io_msg_ring_data(struct io_ring_ctx *target_ctx, return -EINVAL; if (!(msg->flags & IORING_MSG_RING_FLAGS_PASS) && msg->dst_fd) return -EINVAL; - if (target_ctx->flags & IORING_SETUP_R_DISABLED) + /* + * Keep IORING_SETUP_R_DISABLED check before submitter_task load + * in io_msg_data_remote() -> io_msg_remote_post() + */ + if (smp_load_acquire(&target_ctx->flags) & IORING_SETUP_R_DISABLED) return -EBADFD; if (io_msg_need_remote(target_ctx)) @@ -244,7 +248,11 @@ static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags) return -EINVAL; if (target_ctx == ctx) return -EINVAL; - if (target_ctx->flags & IORING_SETUP_R_DISABLED) + /* + * Keep IORING_SETUP_R_DISABLED check before submitter_task load + * in io_msg_fd_remote() + */ + if (smp_load_acquire(&target_ctx->flags) & IORING_SETUP_R_DISABLED) return -EBADFD; if (!msg->src_file) { int ret = io_msg_grab_file(req, issue_flags); diff --git a/io_uring/register.c b/io_uring/register.c index d189b266b8cce..db53e664348d7 100644 --- a/io_uring/register.c +++ b/io_uring/register.c @@ -193,7 +193,8 @@ static int io_register_enable_rings(struct io_ring_ctx *ctx) if (ctx->restrictions.registered) ctx->restricted = 1; - ctx->flags &= ~IORING_SETUP_R_DISABLED; + /* Keep submitter_task store before clearing IORING_SETUP_R_DISABLED */ + smp_store_release(&ctx->flags, ctx->flags & ~IORING_SETUP_R_DISABLED); if (ctx->sq_data && wq_has_sleeper(&ctx->sq_data->wait)) wake_up(&ctx->sq_data->wait); return 0; -- 2.51.0