From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x2240zfF3b+ZbSjgiD2gahD8GVwd+KLxAd8iW638HdX4z6EnS0Du9ZjcyvAEFl3KHYFaIM+Dd ARC-Seal: i=1; a=rsa-sha256; t=1517591431; cv=none; d=google.com; s=arc-20160816; b=jbpIQtI6dH2TFzOzZy1NZUJq2fCFwQ+pKT+Wgmn3LQblxP7Z8wSiBIzUejaxdy4EXV w27vJ4UT0huu/bCGJeKk1qBTk67kNA4buPgGVgYwo7gRQUhMTvU0NQdtoXgfw/HCNSio RkG6FnvcoCCIxo8OQ7jeYTzeSyZvQFq1ZtcqOA0p+4BBowU1mIx+iSgBHtnA6JCe/9U9 jvqyuvyPtMJ7CS/SmB7uB76Pihardrp/3QLeJlePpcjuaMFNT9yVCAHVGzPVmJFCDz// y73Bu4EwyJgbWI4zgOVX/qbuMCXTkLh7tTxhDiT8apfO5iRj9s2PGlESBOP+NzWqWBaS QYqQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=kt5p7F6XjwxenMB2sGuif7BSQScpS0vAtVbBtlSXkeA=; b=sAVIAHUwE4KB8hTQlEO0BmnsCLOW9LZa8QY7F6RpniY7IhiZqbQ9w22l2z46KFvddM QXYkAths69aA/xU0ynrKQfqzJFRU8z7oBnfUCZl3d+gbDx+LwLxKul9Mj+Esf0eNC34r TXTn4LCFASfRjpKvInQoL2bVw0FBO+cz4nH1JpQkAbD71lOtt37yjwu1UnbsjN3ptEGO SJY/DPPMSK3vrT5pYPXuDAQb92C+QF+0mzpD8PL12oFbrxLPoC3//lvzmDVWqo9zlCHO G8vbnJPIuRdnI+nMs5FQ9H4M2PP3B8x32Zbc1TRW12Pkk0G/6PYkx84u7e/VpyJDDy6Z 1j8A== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Liu Bo , David Sterba , Sasha Levin Subject: [PATCH 4.14 078/156] Btrfs: fix list_add corruption and soft lockups in fsync Date: Fri, 2 Feb 2018 17:57:39 +0100 Message-Id: <20180202140843.808678497@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180202140840.242829545@linuxfoundation.org> References: <20180202140840.242829545@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1591309952913529844?= X-GMAIL-MSGID: =?utf-8?q?1591309952913529844?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Liu Bo [ Upstream commit ebb70442cdd4872260c2415929c456be3562da82 ] Xfstests btrfs/146 revealed this corruption, [ 58.138831] Buffer I/O error on dev dm-0, logical block 2621424, async page read [ 58.151233] BTRFS error (device sdf): bdev /dev/mapper/error-test errs: wr 1, rd 0, flush 0, corrupt 0, gen 0 [ 58.152403] list_add corruption. prev->next should be next (ffff88005e6775d8), but was ffffc9000189be88. (prev=ffffc9000189be88). [ 58.153518] ------------[ cut here ]------------ [ 58.153892] WARNING: CPU: 1 PID: 1287 at lib/list_debug.c:31 __list_add_valid+0x169/0x1f0 ... [ 58.157379] RIP: 0010:__list_add_valid+0x169/0x1f0 ... [ 58.161956] Call Trace: [ 58.162264] btrfs_log_inode_parent+0x5bd/0xfb0 [btrfs] [ 58.163583] btrfs_log_dentry_safe+0x60/0x80 [btrfs] [ 58.164003] btrfs_sync_file+0x4c2/0x6f0 [btrfs] [ 58.164393] vfs_fsync_range+0x5f/0xd0 [ 58.164898] do_fsync+0x5a/0x90 [ 58.165170] SyS_fsync+0x10/0x20 [ 58.165395] entry_SYSCALL_64_fastpath+0x1f/0xbe ... It turns out that we could record btrfs_log_ctx:io_err in log_one_extents when IO fails, but make log_one_extents() return '0' instead of -EIO, so the IO error is not acknowledged by the callers, i.e. btrfs_log_inode_parent(), which would remove btrfs_log_ctx:list from list head 'root->log_ctxs'. Since btrfs_log_ctx is allocated from stack memory, it'd get freed with a object alive on the list. then a future list_add will throw the above warning. This returns the correct error in the above case. Jeff also reported this while testing against his fsync error patch set[1]. [1]: https://www.spinics.net/lists/linux-btrfs/msg65308.html "btrfs list corruption and soft lockups while testing writeback error handling" Fixes: 8407f553268a4611f254 ("Btrfs: fix data corruption after fast fsync and writeback error") Signed-off-by: Liu Bo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/file.c | 5 +++-- fs/btrfs/tree-log.c | 2 +- 2 files changed, 4 insertions(+), 3 deletions(-) --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2056,6 +2056,8 @@ int btrfs_sync_file(struct file *file, l len = (u64)end - (u64)start + 1; trace_btrfs_sync_file(file, datasync); + btrfs_init_log_ctx(&ctx, inode); + /* * We write the dirty pages in the range and wait until they complete * out of the ->i_mutex. If so, we can flush the dirty pages by @@ -2202,8 +2204,6 @@ int btrfs_sync_file(struct file *file, l } trans->sync = true; - btrfs_init_log_ctx(&ctx, inode); - ret = btrfs_log_dentry_safe(trans, root, dentry, start, end, &ctx); if (ret < 0) { /* Fallthrough and commit/free transaction. */ @@ -2261,6 +2261,7 @@ int btrfs_sync_file(struct file *file, l ret = btrfs_end_transaction(trans); } out: + ASSERT(list_empty(&ctx.list)); err = file_check_and_advance_wb_err(file); if (!ret) ret = err; --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -4100,7 +4100,7 @@ static int log_one_extent(struct btrfs_t if (ordered_io_err) { ctx->io_err = -EIO; - return 0; + return ctx->io_err; } btrfs_init_map_token(&token);