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=-9.6 required=3.0 tests=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=ham 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 0D9C9C3A5A9 for ; Mon, 4 May 2020 15:32:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E3C222075A for ; Mon, 4 May 2020 15:32:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="XTPPH0DQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729375AbgEDPcL (ORCPT ); Mon, 4 May 2020 11:32:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726908AbgEDPcK (ORCPT ); Mon, 4 May 2020 11:32:10 -0400 Received: from mail-pg1-x542.google.com (mail-pg1-x542.google.com [IPv6:2607:f8b0:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67573C061A0E for ; Mon, 4 May 2020 08:32:10 -0700 (PDT) Received: by mail-pg1-x542.google.com with SMTP id j21so612087pgb.7 for ; Mon, 04 May 2020 08:32:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=6x/gkPpdUu5ZmCBu+qA+TYPM/TczyqfC7nUcr3D0L1k=; b=XTPPH0DQ0On3AJBqn12M+3nev/cwzx+gz00/YUky/lwUu6RbphgQjtpuZlqjH+XaM4 bEuVcKAZ+5bOsrtkY77Qm+ZWBkSphxa2KPb152eY5jVMtuw1YKMSEamDWLtZ0IDLhufE /OxOfjLf7XzKtQLjPznBqcoGl3UONq7vS1j08DscuQ81NvDYIZTqEfUrcOU5C6O2mn7u OpKYoC1AH3D56+CBzrWckRFAyTN4JeAv4Ai98hs9+F1WJHmsh4O7oczY+T3GQJeJZk0F MuOsgUt2KOWnAUbAMxlsaFmUS/F2UmOsjYzyfnirTebXu9aFgen9wcwbzIl1JrrXQJoH KI/Q== 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; bh=6x/gkPpdUu5ZmCBu+qA+TYPM/TczyqfC7nUcr3D0L1k=; b=s8abxsUO8a94CRltpKpEAp+5zuE1G2a08eS3AIfxybzcGW95i+vxEjfihvLgyjd0ux f2J96og2lA7SPcAFBzFL187q7bVCYH34bSu8IoZ51v2Ydthquis0EncU6+le3HdPNmA0 Q1trsrr4Yy+5zR0NQlDyHAdvLZMxmUb2FcWzYjYD84OhWfBZSMyK89n8BsLrr/10V/SL qBm0jUIyF+k482IBmRc3BRMLa6F80+blXhYSyvJKaQBWUf2y5YzQxaFqHMXD3PJFqFiv 2/4BzLu8DQUhb0xafcZDsuqIg3oQFj2gLbc8hG3YrmIcceMW0TMXtL9dZY3avQjy0I71 SblQ== X-Gm-Message-State: AGi0PubX2mNd5NLJRW21k+NmGVvtdt7f24pKa3LWUzotpqFGd5Shvoy0 Rg3s5oMurTnFD2QWr37KCYc= X-Google-Smtp-Source: APiQypLR7YUeSVYAK2wE39xo97f1yngB2mL78CcKaxaBSUitWDFxaVQ1+ct/1M+wrWIFt23hN6kjgA== X-Received: by 2002:a63:a043:: with SMTP id u3mr16617563pgn.287.1588606329912; Mon, 04 May 2020 08:32:09 -0700 (PDT) Received: from localhost.localdomain ([120.244.110.63]) by smtp.gmail.com with ESMTPSA id l137sm9226518pfd.107.2020.05.04.08.32.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 May 2020 08:32:09 -0700 (PDT) From: Jia-Ju Bai To: shaggy@kernel.org Cc: jfs-discussion@lists.sourceforge.net, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH] fs: jfs: fix a possible data race in metapage_writepage() Date: Mon, 4 May 2020 23:31:38 +0800 Message-Id: <20200504153138.13464-1-baijiaju1990@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The functions metapage_writepage() and lmPostGC() can be concurrently executed in the following call contexts: Thread1: metapage_writepage() Thread2: lbmIODone() lmPostGC() In metapage_writepage(): if (mp->log && !(mp->log->cflag & logGC_PAGEOUT)) In lmPostGC(): spin_lock_irqsave(&log->gclock, flags); ... log->cflag &= ~logGC_PAGEOUT ... spin_unlock_irqrestore(&log->gclock, flags); The memory addresses of mp->log->cflag and log->cflag can be identical, and thus a data race can occur. To fix this data race, the spinlock mp->log->gclock is used in metapage_writepage(). This data race is found by our concurrency fuzzer. Signed-off-by: Jia-Ju Bai --- fs/jfs/jfs_metapage.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c index a2f5338a5ea1..026c11b2572d 100644 --- a/fs/jfs/jfs_metapage.c +++ b/fs/jfs/jfs_metapage.c @@ -351,6 +351,7 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc) unsigned long bio_offset = 0; int offset; int bad_blocks = 0; + uint cflag; page_start = (sector_t)page->index << (PAGE_SHIFT - inode->i_blkbits); @@ -370,8 +371,14 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc) * Make sure this page isn't blocked indefinitely. * If the journal isn't undergoing I/O, push it */ - if (mp->log && !(mp->log->cflag & logGC_PAGEOUT)) - jfs_flush_journal(mp->log, 0); + + if (mp->log) { + spin_lock_irq(&mp->log->gclock); + cflag = mp->log->cflag; + spin_unlock_irq(&mp->log->gclock); + if (!(cflag & logGC_PAGEOUT)) + jfs_flush_journal(mp->log, 0); + } continue; } -- 2.17.1