From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cantor2.suse.de ([195.135.220.15]:33622 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751960AbaE1Q7H (ORCPT ); Wed, 28 May 2014 12:59:07 -0400 Date: Wed, 28 May 2014 18:59:06 +0200 From: David Sterba To: Adam Buchbinder Cc: linux-btrfs@vger.kernel.org Subject: Re: [PATCH] btrfs-image: Fix a data race in build_chunk_tree. Message-ID: <20140528165906.GR5346@twin.jikos.cz> Reply-To: dsterba@suse.cz References: <1400478042-19837-1-git-send-email-abuchbinder@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1400478042-19837-1-git-send-email-abuchbinder@google.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Sun, May 18, 2014 at 10:40:42PM -0700, Adam Buchbinder wrote: > A mdrestore_struct was being written to without its mutex being held. > This race was found with ThreadSanitizer; the relevant part of the report > looks like this: > > WARNING: ThreadSanitizer: data race (pid=18828) > Write of size 8 at 0x7fffffc3d088 by main thread: > #0 build_chunk_tree .../btrfs-progs/btrfs-image.c:2233 > #1 __restore_metadump .../btrfs-progs/btrfs-image.c:2294 > #2 restore_metadump .../btrfs-progs/btrfs-image.c:2345 > #3 main .../btrfs-progs/btrfs-image.c:2545 > > Previous read of size 8 at 0x7fffffc3d088 by thread T1 (mutexes: write M0): > #0 restore_worker .../btrfs-progs/btrfs-image.c:1636 > > Location is stack of main thread. > > Mutex M0 created at: > #0 pthread_mutex_init ??:0 > #1 mdrestore_init .../btrfs-progs/btrfs-image.c:1766 > #2 __restore_metadump .../btrfs-progs/btrfs-image.c:2286 > #3 restore_metadump .../btrfs-progs/btrfs-image.c:2345 > #4 main .../btrfs-progs/btrfs-image.c:2545 > > Thread T1 (tid=18830, running) created by main thread at: > #0 pthread_create ??:0 > #1 mdrestore_init .../btrfs-progs/btrfs-image.c:1784 > #2 __restore_metadump .../btrfs-progs/btrfs-image.c:2286 > #3 restore_metadump .../btrfs-progs/btrfs-image.c:2345 > #4 main .../btrfs-progs/btrfs-image.c:2545 > --- Thanks. FYI, I've added your Signed-off-by line, same as in the other patch you've sent.