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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 B8AE5C07E9B for ; Mon, 19 Jul 2021 16:27:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A6C9F6141C for ; Mon, 19 Jul 2021 16:27:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346205AbhGSPqy (ORCPT ); Mon, 19 Jul 2021 11:46:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:58356 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344872AbhGSPAA (ORCPT ); Mon, 19 Jul 2021 11:00:00 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id CBCF060238; Mon, 19 Jul 2021 15:40:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626709239; bh=C1ShubNXVTEITTM499ROiCEtSal1Awt21Bbup50aTP8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=j2AgVtmQW8mpqPpvDy8Re29wcXCFy3pokOIHMEQEf7MqekMcJbnBTRu9KwZbvZrzB g0bbOq4IKhW5WoV/hwbkffQ3s1gbyM1XpnhbgMdH93pbQVzVkVQzCE6Q+euKlhXv2r yM0HV1srd/gfR3E75TybmF5QfFgi483+9K8owqmI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hou Tao , Mike Snitzer Subject: [PATCH 4.19 305/421] dm btree remove: assign new_root only when removal succeeds Date: Mon, 19 Jul 2021 16:51:56 +0200 Message-Id: <20210719144956.900812687@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144946.310399455@linuxfoundation.org> References: <20210719144946.310399455@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hou Tao commit b6e58b5466b2959f83034bead2e2e1395cca8aeb upstream. remove_raw() in dm_btree_remove() may fail due to IO read error (e.g. read the content of origin block fails during shadowing), and the value of shadow_spine::root is uninitialized, but the uninitialized value is still assign to new_root in the end of dm_btree_remove(). For dm-thin, the value of pmd->details_root or pmd->root will become an uninitialized value, so if trying to read details_info tree again out-of-bound memory may occur as showed below: general protection fault, probably for non-canonical address 0x3fdcb14c8d7520 CPU: 4 PID: 515 Comm: dmsetup Not tainted 5.13.0-rc6 Hardware name: QEMU Standard PC RIP: 0010:metadata_ll_load_ie+0x14/0x30 Call Trace: sm_metadata_count_is_more_than_one+0xb9/0xe0 dm_tm_shadow_block+0x52/0x1c0 shadow_step+0x59/0xf0 remove_raw+0xb2/0x170 dm_btree_remove+0xf4/0x1c0 dm_pool_delete_thin_device+0xc3/0x140 pool_message+0x218/0x2b0 target_message+0x251/0x290 ctl_ioctl+0x1c4/0x4d0 dm_ctl_ioctl+0xe/0x20 __x64_sys_ioctl+0x7b/0xb0 do_syscall_64+0x40/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae Fixing it by only assign new_root when removal succeeds Signed-off-by: Hou Tao Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/persistent-data/dm-btree-remove.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/md/persistent-data/dm-btree-remove.c +++ b/drivers/md/persistent-data/dm-btree-remove.c @@ -549,7 +549,8 @@ int dm_btree_remove(struct dm_btree_info delete_at(n, index); } - *new_root = shadow_root(&spine); + if (!r) + *new_root = shadow_root(&spine); exit_shadow_spine(&spine); return r;