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=-0.7 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 2A425C64EB4 for ; Sun, 2 Dec 2018 02:13:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E380F2081C for ; Sun, 2 Dec 2018 02:13:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E380F2081C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-block-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725759AbeLBN1A (ORCPT ); Sun, 2 Dec 2018 08:27:00 -0500 Received: from mail-io1-f72.google.com ([209.85.166.72]:37149 "EHLO mail-io1-f72.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725731AbeLBN1A (ORCPT ); Sun, 2 Dec 2018 08:27:00 -0500 Received: by mail-io1-f72.google.com with SMTP id d63so10391302iog.4 for ; Sat, 01 Dec 2018 18:13:04 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:in-reply-to:message-id:subject :from:to; bh=LINITKU8wtxfed/nAUhJDbpO45KO4FFUqwUKZ0LL3S4=; b=TTWhvtdz96r150yz6WSJ76bVXdwFimJNlCWYj69bJKdaDPV81BzBQsEh2+tXgKzqvf BU+WxkhMUh3uuDf7W0eWZe/lDYWRbGF+fAx/LzYAUfB6c7cjG9Vy+jhJ8ftOC45RTorj yE4X3VNNwhNO6CdnMiCi+tisTAAEsULlzrzhEVWpYR0aOI3tFtXhMcmdJaOQy4gChL/P fLpeRzAuvXydGISotCoJx1b9ILbw2/qL0pmAii+6Q5hml+dnKnraw+apfLw0lkascuOF a/vztfogIxv9te1iQu6FwCBx+k3IpFxu3nGNhhQr0jbOOwIJfyt/kNZVdgRHklISVvi2 9aDw== X-Gm-Message-State: AA+aEWY7dJHl01WwC8Wy6anmK3DuZlqHgcQG04s97wZIwCefmau00MZ4 FqboHygUS69DrcHJ9dDnu1bmJcW1DFDdXOnr7iTgdLEGLqzk X-Google-Smtp-Source: AFSGD/WpOIKbi/AlCK3X44i2JPxN+zz6/C23NM3KbtxrClh3EsHrHHU7QDiOgKJcHwStNQSlz2c6lBejIfTKbiaLIPrbPDw3bI0S MIME-Version: 1.0 X-Received: by 2002:a24:42c3:: with SMTP id i186mr3551971itb.2.1543716784234; Sat, 01 Dec 2018 18:13:04 -0800 (PST) Date: Sat, 01 Dec 2018 18:13:04 -0800 In-Reply-To: <000000000000140c370577db5ece@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000008eedbd057c00922c@google.com> Subject: Re: KASAN: use-after-free Read in debugfs_remove (3) From: syzbot To: axboe@kernel.dk, gregkh@linuxfoundation.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, rafael@kernel.org, rostedt@goodmis.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: d8f190ee836a Merge branch 'akpm' (patches from Andrew) git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17cfcab9400000 kernel config: https://syzkaller.appspot.com/x/.config?x=4602730af4f872ef dashboard link: https://syzkaller.appspot.com/bug?extid=903b72a010ad6b7a40f2 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12adc87d400000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12feb87d400000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+903b72a010ad6b7a40f2@syzkaller.appspotmail.com sshd (5946) used greatest stack depth: 15744 bytes left ================================================================== BUG: KASAN: use-after-free in debugfs_remove+0x10b/0x130 fs/debugfs/inode.c:682 Read of size 8 at addr ffff8881b6a51bc0 by task kworker/0:2/2931 CPU: 0 PID: 2931 Comm: kworker/0:2 Not tainted 4.20.0-rc4+ #358 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events __blk_release_queue Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x244/0x39d lib/dump_stack.c:113 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 debugfs_remove+0x10b/0x130 fs/debugfs/inode.c:682 blk_trace_free+0x35/0x130 kernel/trace/blktrace.c:312 blk_trace_cleanup kernel/trace/blktrace.c:339 [inline] __blk_trace_remove+0x7a/0xa0 kernel/trace/blktrace.c:352 blk_trace_shutdown+0x63/0x80 kernel/trace/blktrace.c:752 __blk_release_queue+0x235/0x510 block/blk-sysfs.c:865 process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Allocated by task 5965: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554 __d_alloc+0xc8/0xb90 fs/dcache.c:1599 d_alloc+0x96/0x380 fs/dcache.c:1678 d_alloc_parallel+0x15a/0x1f40 fs/dcache.c:2421 __lookup_slow+0x1e6/0x540 fs/namei.c:1654 lookup_one_len+0x1d8/0x220 fs/namei.c:2543 start_creating+0xc6/0x200 fs/debugfs/inode.c:308 __debugfs_create_file+0x63/0x400 fs/debugfs/inode.c:347 debugfs_create_file+0x57/0x70 fs/debugfs/inode.c:399 do_blk_trace_setup+0x45d/0xdb0 kernel/trace/blktrace.c:528 __blk_trace_setup+0xd5/0x180 kernel/trace/blktrace.c:577 blk_trace_ioctl+0x17a/0x2f0 kernel/trace/blktrace.c:716 blkdev_ioctl+0x9e9/0x21b0 block/ioctl.c:591 block_ioctl+0xee/0x130 fs/block_dev.c:1883 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe kobject: 'slaves' (00000000689664f7): kobject_add_internal: parent: 'loop0', set: '' Freed by task 0: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kmem_cache_free+0x83/0x290 mm/slab.c:3760 __d_free+0x20/0x30 fs/dcache.c:257 __rcu_reclaim kernel/rcu/rcu.h:240 [inline] rcu_do_batch kernel/rcu/tree.c:2437 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2716 [inline] rcu_process_callbacks+0x100a/0x1ac0 kernel/rcu/tree.c:2697 kobject: 'loop0' (000000009adfb848): kobject_uevent_env __do_softirq+0x308/0xb7e kernel/softirq.c:292 kobject: 'loop0' (000000009adfb848): fill_kobj_path: path = '/devices/virtual/block/loop0' The buggy address belongs to the object at ffff8881b6a51b80 which belongs to the cache dentry of size 288 kobject: 'queue' (00000000d475bda4): kobject_add_internal: parent: 'loop0', set: '' The buggy address is located 64 bytes inside of 288-byte region [ffff8881b6a51b80, ffff8881b6a51ca0) The buggy address belongs to the page: page:ffffea0006da9440 count:1 mapcount:0 mapping:ffff8881da980c80 index:0x0 flags: 0x2fffc0000000200(slab) raw: 02fffc0000000200 ffffea0006da8448 ffffea0006da94c8 ffff8881da980c80 raw: 0000000000000000 ffff8881b6a51080 000000010000000b 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881b6a51a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb kobject: 'mq' (00000000a3db6337): kobject_add_internal: parent: 'loop0', set: '' ffff8881b6a51b00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff8881b6a51b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881b6a51c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881b6a51c80: fb fb fb fb fc fc fc fc fc fc fc fc 00 00 00 00 ==================================================================