From patchwork Thu Nov 5 22:31:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Begunkov X-Patchwork-Id: 319933 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=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 E8759C4742C for ; Thu, 5 Nov 2020 22:34:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9222920867 for ; Thu, 5 Nov 2020 22:34:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rYpLblmS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732035AbgKEWes (ORCPT ); Thu, 5 Nov 2020 17:34:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726729AbgKEWer (ORCPT ); Thu, 5 Nov 2020 17:34:47 -0500 Received: from mail-wm1-x344.google.com (mail-wm1-x344.google.com [IPv6:2a00:1450:4864:20::344]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8DA33C0613CF; Thu, 5 Nov 2020 14:34:47 -0800 (PST) Received: by mail-wm1-x344.google.com with SMTP id c18so3118692wme.2; Thu, 05 Nov 2020 14:34:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=e4sm3HrRlnJ71AFKp4V3p/GrKt1dk+1gQo/oWyUt11s=; b=rYpLblmSgRF73CX58czKd0ZDvoG+EYNtWKpJCV7hKC3Y6fpztqzZaxO5X620SSodPs DTelR9erOdQsu8ISWjEFLu2vuS7S2c/MrfL87TrgUJIlqawg9ZjipuTFXg/ukyFYQzAj Y80jmfK2VkVlJj8OcGV1eUG8dl44CQnpallc49LzJiEI9IuVPyqZDItwGP0Cy0YOeEJu cf4mlXYGaBZhj1b9W+Jv2WuoF4vYYEBSFvtqDntyX+xRYCdvJ2u8CuWkbPHSN2Ti5tAh MbfmpwyYD54OeOY1s1gtARWOOzNGvBir9/DUFhEiZGXapgLgO8BV4nA2qXTHFFGoCFp0 qhPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=e4sm3HrRlnJ71AFKp4V3p/GrKt1dk+1gQo/oWyUt11s=; b=sj7raneWw59vlvXTAP5CNE+SJIOrB3Yflac6rFVVBzBQRmP2vYrFrak1FU4KSkzOdp 14pqC8jt3AhdhVN4mUxNUwF7lluki23jTuL/uCa3p5OhxRWZmdjHfFmcqVE8vTTFyxXF KUJSlc3ImUfNeNq8sveoSoJg5Q2pXQrz0yQ7FzZQW3exyk7BZg4NyKFoxzl7neYC1UV0 71q+d4xyizuOO96lPvaxEoQbSeL6IAprhgw+Je2/eXHnkHRerqcvSSWFnPlv7kBfb3o+ 8NWhtGXruApK9LIXDCgW7cUP042TyLZp4tAplj9jOSl12YAS13Rj+1C6gj+TL+CmGVLM LK6A== X-Gm-Message-State: AOAM531+zEx6Cx308jhceTa+53PVITEA5jDiqWx3eSWr5lxiN+qlhEgY 4rPQyn1eqCzifqKKIEBUMz3nbhsrVa4= X-Google-Smtp-Source: ABdhPJy2FrsEhnxVfuKDBliXlLQ9JW+UbhHlfAtmup1dJdrzWqngbrL6jmTkwfCfxEGcfEBYz4wDpw== X-Received: by 2002:a1c:2c43:: with SMTP id s64mr4854419wms.130.1604615686347; Thu, 05 Nov 2020 14:34:46 -0800 (PST) Received: from localhost.localdomain (host109-152-100-164.range109-152.btcentralplus.com. [109.152.100.164]) by smtp.gmail.com with ESMTPSA id f23sm4292322wmb.43.2020.11.05.14.34.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Nov 2020 14:34:45 -0800 (PST) From: Pavel Begunkov To: Jens Axboe , io-uring@vger.kernel.org Cc: stable@vger.kernel.org Subject: [PATCH 5.10] io_uring: fix link lookup racing with link timeout Date: Thu, 5 Nov 2020 22:31:37 +0000 Message-Id: X-Mailer: git-send-email 2.24.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org We can't just go over linked requests because it may race with linked timeouts. Take ctx->completion_lock in that case. Cc: stable@vger.kernel.org # v5.7+ Signed-off-by: Pavel Begunkov --- fs/io_uring.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 29f1417690d5..8018c7076b25 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -8470,7 +8470,21 @@ static bool io_timeout_remove_link(struct io_ring_ctx *ctx, static bool io_cancel_link_cb(struct io_wq_work *work, void *data) { - return io_match_link(container_of(work, struct io_kiocb, work), data); + struct io_kiocb *req = container_of(work, struct io_kiocb, work); + bool ret; + + if (req->flags & REQ_F_LINK_TIMEOUT) { + unsigned long flags; + struct io_ring_ctx *ctx = req->ctx; + + /* protect against races with linked timeouts */ + spin_lock_irqsave(&ctx->completion_lock, flags); + ret = io_match_link(req, data); + spin_unlock_irqrestore(&ctx->completion_lock, flags); + } else { + ret = io_match_link(req, data); + } + return ret; } static void io_attempt_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req)