From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793208015; b=5ZMsU6bbIU8ZjJDCVZc0/MlJ8yvoPEmVOEP2Mms4BlTcAgAndCsHA4panx+xsksnhaEf IKKdNmolQAwLnzoW+bUCjQDR/V03APqyGG76kYzXWj5D8qz9Dc3C4D/hoyyETKRUIMohG w8kHj40kB6iLvJ2tXmD/KArL4sZAyg3fOybKKgiskD5IbxxXVXW8tt4Qqa3DIcRuXDrfC +g6X157NZ0BoXZyNpre6llvaqnogh30YwNNeshgydHrgh2el2BhDXQ/z+hP6wmf1QqYvr 1/o9cb4f+lAGc0cD53r1mS5KJRH/TmaHp6rJKypCccJiD+3tU28kYjaNq00ioCcpVWA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793208015; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=2OcEIY6g5zNqUvHL0wCpgnfICtkTYSu3ZmZAyuOg3Z0=; b=wc5VX5rgNInQfalopccaupIa6Fdwgjx5tVvr6oiPtIPignBPNr0712KrGPqycWVeM1eY eeqWBSPeGLHYPBCuc6960snJXCpPa1rsYv0Mgx/4eovOkWcBlfnG2982UWr1qPnYQS9EU V35Twmee5BtO4oABdt3wwl63mvqisYMCBv3rdMa6TTxyp4k/O+7JUTczOKpL7aBD1gfv+ NcAYVx+IcS00M2TKHtDw8miviyHbezxRgnx+XjrbS0GTJ82vHORcMhywZJQrRv4SZUB45 Btkj0ah25R3CRoK6KU8w/JntYWm/7iIv/Dj/iyBI1HAHYu5V7smZXJY3fr171n3RnYA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=STNACcl0; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 034FC606A31A; Wed, 28 Oct 2026 17:20:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=STNACcl0 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 51D5A1F01828; Wed, 28 Oct 2026 17:20:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793208014; bh=2OcEIY6g5zNqUvHL0wCpgnfICtkTYSu3ZmZAyuOg3Z0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=STNACcl0OpeQS2SxLQpz8ZkmWSEPSFepfIGAZqX3mkajFt/NSDskHdkL2hamAR0q6 H8qGqPpjyFI64NV/T0HDb8Lys1hbHK2cK1/6rolh4bLkc4qGLrDC1/eCM1xf1Ov3Vz RQ2xWHofac+ctQVXnBqDkgbFexPJPv7sdxK1Pc9g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Josef Bacik , Jens Axboe Subject: [PATCH 6.12 217/247] io_uring: dont pass restart error codes to userspace Date: Wed, 28 Oct 2026 18:00:20 +0100 Message-ID: <20261028165952.561663491@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165947.349197979@linuxfoundation.org> References: <20261028165947.349197979@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josef Bacik Commit e1a64bc64897f4c2fe460922c345f2ed8f889b5f upstream. -ERESTARTSYS and friends are instructions for the system call exit code, which either restarts the call or turns them into -EINTR. They are not supposed to be seen by applications. A request isn't a system call, nobody looks at what it returns before that is put into a CQE. The read/write and the networking opcodes convert these codes to -EINTR by hand. The others don't. An io-wq worker that is blocked in the open of a FIFO, a tty or some other device, or in a splice from an empty pipe, and that gets interrupted because the request is cancelled, completes it with -512: IORING_OP_OPENAT, IOSQE_ASYNC // FIFO without a writer IORING_OP_ASYNC_CANCEL // -EALREADY, worker is signalled CQE of the open: res == -512 There are more candidates, like whatever a file system or driver returns from ->flush(), ->fsync(), ->fallocate() or ->uring_cmd(), or breaking a lease or delegation. Take care of it in io_issue_sqe(), which all of them go through. The helper is moved from rw.c as is. The cost is a compare and a branch that is not taken per request. Fixes: 15b71abe7b52 ("io_uring: add support for IORING_OP_OPENAT") Assisted-by: LLM Signed-off-by: Josef Bacik Link: https://patch.msgid.link/20261015-b4-io-uring-fixes-v1-39-c1556f5d7bf5@toxicpanda.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- io_uring/io_uring.c | 5 +++++ io_uring/io_uring.h | 18 ++++++++++++++++++ io_uring/rw.c | 18 ------------------ 3 files changed, 23 insertions(+), 18 deletions(-) --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1773,6 +1773,9 @@ static int io_issue_sqe(struct io_kiocb } if (ret == IOU_OK) { + /* not all handlers take care of the internal restart codes */ + if (unlikely(req->cqe.res <= -ERESTARTSYS)) + req->cqe.res = io_fixup_restart_res(req->cqe.res); if (issue_flags & IO_URING_F_COMPLETE_DEFER) io_req_complete_defer(req); else @@ -1788,6 +1791,8 @@ static int io_issue_sqe(struct io_kiocb if ((req->ctx->flags & IORING_SETUP_IOPOLL) && def->iopoll_queue) io_iopoll_req_issued(req, issue_flags); } + if (unlikely(ret <= -ERESTARTSYS)) + ret = io_fixup_restart_res(ret); return ret; } --- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -203,6 +203,24 @@ static __always_inline bool io_fill_cqe_ return true; } +static inline ssize_t io_fixup_restart_res(ssize_t ret) +{ + switch (ret) { + case -ERESTARTSYS: + case -ERESTARTNOINTR: + case -ERESTARTNOHAND: + case -ERESTART_RESTARTBLOCK: + /* + * We can't just restart the syscall, since previously + * submitted sqes may already be in progress. Just fail + * this IO with EINTR. + */ + return -EINTR; + default: + return ret; + } +} + static inline void req_set_fail(struct io_kiocb *req) { req->flags |= REQ_F_FAIL; --- a/io_uring/rw.c +++ b/io_uring/rw.c @@ -560,24 +560,6 @@ static void io_complete_rw_iopoll(struct smp_store_release(&req->iopoll_completed, 1); } -static inline ssize_t io_fixup_restart_res(ssize_t ret) -{ - switch (ret) { - case -ERESTARTSYS: - case -ERESTARTNOINTR: - case -ERESTARTNOHAND: - case -ERESTART_RESTARTBLOCK: - /* - * We can't just restart the syscall, since previously - * submitted sqes may already be in progress. Just fail - * this IO with EINTR. - */ - return -EINTR; - default: - return ret; - } -} - static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) { /* IO was queued async, completion will happen later */