From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5390BC433E1 for ; Fri, 5 Jun 2020 14:25:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3478320663 for ; Fri, 5 Jun 2020 14:25:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591367103; bh=0S8H3cUhAiZf8diHXmSrml5+cVPZLK2++DqPF6FkBPw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0Sm9+pftmPXHy4KNZCRuhnNPh33WzVQ5/UoyeX1shtwMGrCr3iYV9eOaMGxOQ5h39 cZbRAB8yhoyqpBpvCXEHO8HVJvh/ju7qn+flYixZsDGTWYfRhK3sK3XDJt8L0HagcG wJon1G9NNyZiSANB9RVqV1vQKUi0mGzOK86a/4uU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728357AbgFEOQ6 (ORCPT ); Fri, 5 Jun 2020 10:16:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:45950 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728295AbgFEOQq (ORCPT ); Fri, 5 Jun 2020 10:16:46 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1A5EF208A7; Fri, 5 Jun 2020 14:16:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591366605; bh=0S8H3cUhAiZf8diHXmSrml5+cVPZLK2++DqPF6FkBPw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KM+E6zI7JSL9C7NtKkJimAcNOb7zcpkJCqKe7y2huEs5FrX5KQp2QLtgW444yUtA8 t7jVQNOQep+ht2SSahPfpTH6gIg3UQYjNMiUzxfzmglcpbiD4Ak4w8KD31G9tWqaiX 0WZpXvXVGubMy2cgV5LbSXky5NSAdbM12Iz+xQUI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jens Axboe , Xiaoguang Wang , Sasha Levin Subject: [PATCH 5.6 20/43] io_uring: reset -EBUSY error when io sq thread is waken up Date: Fri, 5 Jun 2020 16:14:50 +0200 Message-Id: <20200605140153.581180425@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200605140152.493743366@linuxfoundation.org> References: <20200605140152.493743366@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Xiaoguang Wang [ Upstream commit d4ae271dfaae2a5f41c015f2f20d62a1deeec734 ] In io_sq_thread(), currently if we get an -EBUSY error and go to sleep, we will won't clear it again, which will result in io_sq_thread() will never have a chance to submit sqes again. Below test program test.c can reveal this bug: int main(int argc, char *argv[]) { struct io_uring ring; int i, fd, ret; struct io_uring_sqe *sqe; struct io_uring_cqe *cqe; struct iovec *iovecs; void *buf; struct io_uring_params p; if (argc < 2) { printf("%s: file\n", argv[0]); return 1; } memset(&p, 0, sizeof(p)); p.flags = IORING_SETUP_SQPOLL; ret = io_uring_queue_init_params(4, &ring, &p); if (ret < 0) { fprintf(stderr, "queue_init: %s\n", strerror(-ret)); return 1; } fd = open(argv[1], O_RDONLY | O_DIRECT); if (fd < 0) { perror("open"); return 1; } iovecs = calloc(10, sizeof(struct iovec)); for (i = 0; i < 10; i++) { if (posix_memalign(&buf, 4096, 4096)) return 1; iovecs[i].iov_base = buf; iovecs[i].iov_len = 4096; } ret = io_uring_register_files(&ring, &fd, 1); if (ret < 0) { fprintf(stderr, "%s: register %d\n", __FUNCTION__, ret); return ret; } for (i = 0; i < 10; i++) { sqe = io_uring_get_sqe(&ring); if (!sqe) break; io_uring_prep_readv(sqe, 0, &iovecs[i], 1, 0); sqe->flags |= IOSQE_FIXED_FILE; ret = io_uring_submit(&ring); sleep(1); printf("submit %d\n", i); } for (i = 0; i < 10; i++) { io_uring_wait_cqe(&ring, &cqe); printf("receive: %d\n", i); if (cqe->res != 4096) { fprintf(stderr, "ret=%d, wanted 4096\n", cqe->res); ret = 1; } io_uring_cqe_seen(&ring, cqe); } close(fd); io_uring_queue_exit(&ring); return 0; } sudo ./test testfile above command will hang on the tenth request, to fix this bug, when io sq_thread is waken up, we reset the variable 'ret' to be zero. Suggested-by: Jens Axboe Signed-off-by: Xiaoguang Wang Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- fs/io_uring.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 504484dc33e4..c6e1f76a6ee0 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5224,6 +5224,7 @@ static int io_sq_thread(void *data) finish_wait(&ctx->sqo_wait, &wait); ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP; + ret = 0; continue; } finish_wait(&ctx->sqo_wait, &wait); -- 2.25.1