From patchwork Tue Mar 24 10:53:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 11455119 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 64FF792A for ; Tue, 24 Mar 2020 10:53:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E83120870 for ; Tue, 24 Mar 2020 10:53:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727485AbgCXKx3 (ORCPT ); Tue, 24 Mar 2020 06:53:29 -0400 Received: from mx2.suse.de ([195.135.220.15]:33800 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727314AbgCXKx3 (ORCPT ); Tue, 24 Mar 2020 06:53:29 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 4A8D0AF39 for ; Tue, 24 Mar 2020 10:53:28 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH 5/6] btrfs-progs: check/original: Fix uninitialized extent buffer contents Date: Tue, 24 Mar 2020 18:53:14 +0800 Message-Id: <20200324105315.136569-6-wqu@suse.com> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200324105315.136569-1-wqu@suse.com> References: <20200324105315.136569-1-wqu@suse.com> MIME-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org [BUG] Valgrind reports the following error for fsck/012: adding new tree backref on start 4206592 len 4096 parent 0 root 5 ==100735== Syscall param pwrite64(buf) points to uninitialised byte(s) ==100735== at 0x49F303A: pwrite (in /usr/lib/libpthread-2.31.so) ==100735== by 0x1A5C85: write_extent_to_disk (extent_io.c:815) ==100735== by 0x1B2507: write_and_map_eb (disk-io.c:512) ==100735== by 0x1B26A7: write_tree_block (disk-io.c:545) ==100735== by 0x1D4822: __commit_transaction (transaction.c:148) ==100735== by 0x1D4AA2: btrfs_commit_transaction (transaction.c:213) ==100735== by 0x16360D: fixup_extent_refs (main.c:7662) ==100735== by 0x16449F: check_extent_refs (main.c:8033) ==100735== by 0x166199: check_chunks_and_extents (main.c:8786) ==100735== by 0x166441: do_check_chunks_and_extents (main.c:8842) ==100735== by 0x169D13: cmd_check (main.c:10324) ==100735== by 0x11CDC6: cmd_execute (commands.h:125) ==100735== Address 0x4e8aeb0 is 128 bytes inside a block of size 4,224 alloc'd ==100735== at 0x483BB65: calloc (vg_replace_malloc.c:762) ==100735== by 0x1A54C5: __alloc_extent_buffer (extent_io.c:609) ==100735== by 0x1A5AD1: alloc_extent_buffer (extent_io.c:752) ==100735== by 0x1B1A0A: btrfs_find_create_tree_block (disk-io.c:222) ==100735== by 0x1BD4A2: btrfs_alloc_free_block (extent-tree.c:2538) ==100735== by 0x1A8CE3: __btrfs_cow_block (ctree.c:322) ==100735== by 0x1A91C6: btrfs_cow_block (ctree.c:415) ==100735== by 0x1AB16C: btrfs_search_slot (ctree.c:1185) ==100735== by 0x160BBC: delete_extent_records (main.c:6652) ==100735== by 0x16343F: fixup_extent_refs (main.c:7629) ==100735== by 0x16449F: check_extent_refs (main.c:8033) ==100735== by 0x166199: check_chunks_and_extents (main.c:8786) ==100735== [CAUSE] For new extent buffer allocated, we don't initialize its content. This is not a major concern, at all. For the above report, the reported range is inside the unused part of the extent buffer, thus won't cause anything. Regular btrfs_cow_block() will cover all the used ranges of one extent buffer. [FIX] But still, since kernel initialize the extent buffer with 0, it won't hurt to do extra initialized to make valgrind happy. Signed-off-by: Qu Wenruo --- extent_io.c | 1 + 1 file changed, 1 insertion(+) diff --git a/extent_io.c b/extent_io.c index f11917a4c6fc..4b5acb1aabf0 100644 --- a/extent_io.c +++ b/extent_io.c @@ -622,6 +622,7 @@ static struct extent_buffer *__alloc_extent_buffer(struct btrfs_fs_info *info, eb->tree = &info->extent_cache; INIT_LIST_HEAD(&eb->recow); INIT_LIST_HEAD(&eb->lru); + memset_extent_buffer(eb, 0, 0, blocksize); return eb; }