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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 91FFEC433E1 for ; Fri, 19 Jun 2020 14:53:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 739D0217D8 for ; Fri, 19 Jun 2020 14:53:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592578420; bh=bGLWixPhjL+vxRiSlHeu3NEuwsW0UJMOZztKFqiUYug=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=KO+WjgHijRI/bmGZoTbgdAAhxaxC9xfk9zGbZJnkza7rKdKeH+YE80YDH2sTp/2Ku BAFkWLC8MtdgKbF3JRCBODef+d8vea3esq2t+PKm6SUZ3LcANjfe9dthx4OJgtPJYz 9SfIVfUmfPpuJQeSS2x6XREU8WaPhvGRpNPUMPS0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389744AbgFSOxi (ORCPT ); Fri, 19 Jun 2020 10:53:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:47908 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389731AbgFSOxe (ORCPT ); Fri, 19 Jun 2020 10:53:34 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5419A21852; Fri, 19 Jun 2020 14:53:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592578413; bh=bGLWixPhjL+vxRiSlHeu3NEuwsW0UJMOZztKFqiUYug=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KEYSiQIiMiLvgvD7lvb9j2r5d30vvCHdy0X4sQcq4i7wZX0ywW0ONgELnZaTFNWTf f2Zne0pfDG4ASwEoeNSj/JIvouQonjqt9vzhsQNxKYUBVyum/ul7ZDcDUkURE/BA1T txfb1A0XjboFkmhleWxM17WJdFXORjvFCTBhHCnk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nikolay Borisov , Qu Wenruo , David Sterba , Vikash Bansal Subject: [PATCH 4.19 013/267] btrfs: Detect unbalanced tree with empty leaf before crashing btree operations Date: Fri, 19 Jun 2020 16:29:58 +0200 Message-Id: <20200619141649.495092948@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141648.840376470@linuxfoundation.org> References: <20200619141648.840376470@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Qu Wenruo commit 62fdaa52a3d00a875da771719b6dc537ca79fce1 upstream. [BUG] With crafted image, btrfs will panic at btree operations: kernel BUG at fs/btrfs/ctree.c:3894! invalid opcode: 0000 [#1] SMP PTI CPU: 0 PID: 1138 Comm: btrfs-transacti Not tainted 5.0.0-rc8+ #9 RIP: 0010:__push_leaf_left+0x6b6/0x6e0 RSP: 0018:ffffc0bd4128b990 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffa0a4ab8f0e38 RCX: 0000000000000000 RDX: ffffa0a280000000 RSI: 0000000000000000 RDI: ffffa0a4b3814000 RBP: ffffc0bd4128ba38 R08: 0000000000001000 R09: ffffc0bd4128b948 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000240 R13: ffffa0a4b556fb60 R14: ffffa0a4ab8f0af0 R15: ffffa0a4ab8f0af0 FS: 0000000000000000(0000) GS:ffffa0a4b7a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2461c80020 CR3: 000000022b32a006 CR4: 00000000000206f0 Call Trace: ? _cond_resched+0x1a/0x50 push_leaf_left+0x179/0x190 btrfs_del_items+0x316/0x470 btrfs_del_csums+0x215/0x3a0 __btrfs_free_extent.isra.72+0x5a7/0xbe0 __btrfs_run_delayed_refs+0x539/0x1120 btrfs_run_delayed_refs+0xdb/0x1b0 btrfs_commit_transaction+0x52/0x950 ? start_transaction+0x94/0x450 transaction_kthread+0x163/0x190 kthread+0x105/0x140 ? btrfs_cleanup_transaction+0x560/0x560 ? kthread_destroy_worker+0x50/0x50 ret_from_fork+0x35/0x40 Modules linked in: ---[ end trace c2425e6e89b5558f ]--- [CAUSE] The offending csum tree looks like this: checksum tree key (CSUM_TREE ROOT_ITEM 0) node 29741056 level 1 items 14 free 107 generation 19 owner CSUM_TREE ... key (EXTENT_CSUM EXTENT_CSUM 85975040) block 29630464 gen 17 key (EXTENT_CSUM EXTENT_CSUM 89911296) block 29642752 gen 17 <<< key (EXTENT_CSUM EXTENT_CSUM 92274688) block 29646848 gen 17 ... leaf 29630464 items 6 free space 1 generation 17 owner CSUM_TREE item 0 key (EXTENT_CSUM EXTENT_CSUM 85975040) itemoff 3987 itemsize 8 range start 85975040 end 85983232 length 8192 ... leaf 29642752 items 0 free space 3995 generation 17 owner 0 ^ empty leaf invalid owner ^ leaf 29646848 items 1 free space 602 generation 17 owner CSUM_TREE item 0 key (EXTENT_CSUM EXTENT_CSUM 92274688) itemoff 627 itemsize 3368 range start 92274688 end 95723520 length 3448832 So we have a corrupted csum tree where one tree leaf is completely empty, causing unbalanced btree, thus leading to unexpected btree balance error. [FIX] For this particular case, we handle it in two directions to catch it: - Check if the tree block is empty through btrfs_verify_level_key() So that invalid tree blocks won't be read out through btrfs_search_slot() and its variants. - Check 0 tree owner in tree checker NO tree is using 0 as its tree owner, detect it and reject at tree block read time. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202821 Reviewed-by: Nikolay Borisov Signed-off-by: Qu Wenruo Signed-off-by: David Sterba Signed-off-by: Vikash Bansal Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/disk-io.c | 10 ++++++++++ fs/btrfs/tree-checker.c | 6 ++++++ 2 files changed, 16 insertions(+) --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -438,6 +438,16 @@ int btrfs_verify_level_key(struct btrfs_ */ if (btrfs_header_generation(eb) > fs_info->last_trans_committed) return 0; + + /* We have @first_key, so this @eb must have at least one item */ + if (btrfs_header_nritems(eb) == 0) { + btrfs_err(fs_info, + "invalid tree nritems, bytenr=%llu nritems=0 expect >0", + eb->start); + WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG)); + return -EUCLEAN; + } + if (found_level) btrfs_node_key_to_cpu(eb, &found_key, 0); else --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -509,6 +509,12 @@ static int check_leaf(struct btrfs_fs_in owner); return -EUCLEAN; } + /* Unknown tree */ + if (owner == 0) { + generic_err(fs_info, leaf, 0, + "invalid owner, root 0 is not defined"); + return -EUCLEAN; + } key.objectid = owner; key.type = BTRFS_ROOT_ITEM_KEY; key.offset = (u64)-1;