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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 15C48C10F0B for ; Thu, 18 Apr 2019 06:28:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DAC0A21479 for ; Thu, 18 Apr 2019 06:28:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733049AbfDRG2O (ORCPT ); Thu, 18 Apr 2019 02:28:14 -0400 Received: from mx2.suse.de ([195.135.220.15]:47442 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725864AbfDRG2O (ORCPT ); Thu, 18 Apr 2019 02:28:14 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 52C63AF5B for ; Thu, 18 Apr 2019 06:28:13 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH] btrfs: volumes: Check memory allocation failure for alloc_btrfs_bio() Date: Thu, 18 Apr 2019 14:28:07 +0800 Message-Id: <20190418062807.32340-1-wqu@suse.com> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org [BUG] With kmalloc failure injection for submit_one_bio(), btrfs can crash like: BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 #PF error: [WRITE] PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP PTI CPU: 1 PID: 247 Comm: kworker/u8:4 Not tainted 5.1.0-rc5-custom+ #19 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Workqueue: writeback wb_workfn (flush-btrfs-6) RIP: 0010:alloc_btrfs_bio+0x1e/0x30 [btrfs] Code: 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 0f 1f 44 00 00 48 63 f6 48 63 ff 48 8d 7c fe 18 be 40 8d 00 00 48 c1 e7 02 e8 a2 86 94 e0 40 38 00 00 00 00 c7 00 01 00 00 00 c3 0f 1f 40 00 0f 1f 44 00 Call Trace: __btrfs_map_block+0x5ce/0x1210 [btrfs] ? btrfs_bio_counter_inc_blocked+0x3a/0xc0 [btrfs] btrfs_map_bio+0x9a/0x430 [btrfs] btree_submit_bio_hook+0x82/0xb0 [btrfs] submit_one_bio+0x95/0xc0 [btrfs] copy_oldmem_page_encrypted+0x20/0x20 ? write_one_eb+0x18f/0x2a0 [btrfs] ? end_extent_buffer_writeback+0x20/0x20 [btrfs] ? btree_write_cache_pages+0x12c/0x350 [btrfs] ? do_writepages+0x41/0xd0 ? __writeback_single_inode+0x54/0x650 ? writeback_sb_inodes+0x1f9/0x540 ? __writeback_inodes_wb+0x5d/0xb0 ? wb_writeback+0x340/0x4b0 ? wb_workfn+0x410/0x5d0 ? process_one_work+0x294/0x650 ? worker_thread+0x2d/0x3d0 ? process_one_work+0x650/0x650 ? kthread+0x112/0x130 ? kthread_park+0x80/0x80 ? ret_from_fork+0x3a/0x50 ---[ end trace b637169fb8b17c9c ]--- [CAUSE] We just forgot to check the return value of kmalloc. Surprisingly, all alloc_btrfs_bio() callers have handled memory allocation pretty well. [FIX] Check and return if we failed memory allocation. Signed-off-by: Qu Wenruo --- fs/btrfs/volumes.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 78bab7803bda..875d0eee1785 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -5582,6 +5582,8 @@ static struct btrfs_bio *alloc_btrfs_bio(int total_stripes, int real_stripes) sizeof(u64) * (total_stripes), GFP_NOFS|__GFP_NOFAIL); + if (!bbio) + return NULL; atomic_set(&bbio->error, 0); refcount_set(&bbio->refs, 1); -- 2.21.0