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=2.1 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SORTED_RECIPS,SPF_PASS, URIBL_BLOCKED autolearn=no 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 280B3ECDE5F for ; Mon, 23 Jul 2018 19:41:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D606D20685 for ; Mon, 23 Jul 2018 19:41:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D606D20685 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-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388140AbeGWUnp (ORCPT ); Mon, 23 Jul 2018 16:43:45 -0400 Received: from mail-it0-f70.google.com ([209.85.214.70]:34197 "EHLO mail-it0-f70.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388104AbeGWUnp (ORCPT ); Mon, 23 Jul 2018 16:43:45 -0400 Received: by mail-it0-f70.google.com with SMTP id k204-v6so9036742ite.1 for ; Mon, 23 Jul 2018 12:41:02 -0700 (PDT) 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=Oa9XU1EpT0UekDWqk3aPDGzuS/uTKHA9UwP3Ggp9ofI=; b=cGZ/wBhoyD4U1UxUt+VVGax+T4aA547Z3qFhx042lQJhrmgEoh2iNy9bal69qsBXvw NADEJQje5Sp9V1HEK0VbIdvbgNTElYWEmqleUJEyDsnG7QTJ0Jltn2BOz3tqHAWyhi8h 7nMdSgGxcmgp447lhOL75tVqzPLzd2hYjtDFfqjtddX4VR9M9taWgZd+ZZu9HmvhLR+C MnY+8taMJNeGZ0O6LRjUNIn/10GV8ixyx+wy4XOkT8UKoD1oBiYg85LlIaGfkCAC8Lnq IQdZde0MpJnmigW03sJnKM3YQYjAIgSfji1GUeAIO5TuiifohMqeKUe8Lfin+fsvqsLJ 2Okg== X-Gm-Message-State: AOUpUlE8CFiuLt33CGYPJOVUNgf68IXPT4pWxEzSkmrBSrWH5EIn87O7 jDyWRVi9mlF2wsRisMWCFFQ+1mbnmWsSsi6GHPaQo25w2scK X-Google-Smtp-Source: AAOMgpeKfxm/kMbIk/NzzdHCaPI9ZamRxjtD7ODQVp18VO93FPWGI0uv7TuJibYL9MtpigxdOQ8a5f7pAUFOy5SFfuJfy+EH2tR9 MIME-Version: 1.0 X-Received: by 2002:a24:44c8:: with SMTP id o191-v6mr164174ita.1.1532374861993; Mon, 23 Jul 2018 12:41:01 -0700 (PDT) Date: Mon, 23 Jul 2018 12:41:01 -0700 In-Reply-To: <000000000000afbebb0570be9bf3@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000004fe3d80571afd3b9@google.com> Subject: Re: KASAN: use-after-free Read in p9_fd_poll From: syzbot To: davem@davemloft.net, ericvh@gmail.com, linux-kernel@vger.kernel.org, lucho@ionkov.net, netdev@vger.kernel.org, rminnich@sandia.gov, syzkaller-bugs@googlegroups.com, v9fs-developer@lists.sourceforge.net Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: d72e90f33aa4 Linux 4.18-rc6 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=161894c8400000 kernel config: https://syzkaller.appspot.com/x/.config?x=68af3495408deac5 dashboard link: https://syzkaller.appspot.com/bug?extid=0442e6e2f7e1e33b1037 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=1569b51c400000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16e7a978400000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+0442e6e2f7e1e33b1037@syzkaller.appspotmail.com random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) ================================================================== BUG: KASAN: use-after-free in p9_fd_poll+0x280/0x2b0 net/9p/trans_fd.c:238 Read of size 8 at addr ffff8801d6ddf340 by task kworker/0:2/26 CPU: 0 PID: 26 Comm: kworker/0:2 Not tainted 4.18.0-rc6+ #160 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events p9_poll_workfn Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 p9_fd_poll+0x280/0x2b0 net/9p/trans_fd.c:238 p9_poll_mux net/9p/trans_fd.c:617 [inline] p9_poll_workfn+0x463/0x6d0 net/9p/trans_fd.c:1107 process_one_work+0xc73/0x1ba0 kernel/workqueue.c:2153 worker_thread+0x189/0x13c0 kernel/workqueue.c:2296 kthread+0x345/0x410 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 Allocated by task 4581: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620 kmalloc include/linux/slab.h:513 [inline] kzalloc include/linux/slab.h:707 [inline] p9_fd_open net/9p/trans_fd.c:796 [inline] p9_fd_create+0x1a7/0x3f0 net/9p/trans_fd.c:1036 p9_client_create+0x8ed/0x1770 net/9p/client.c:1063 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135 mount_fs+0xae/0x328 fs/super.c:1277 vfs_kern_mount.part.34+0xdc/0x4e0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:1027 [inline] do_new_mount fs/namespace.c:2518 [inline] do_mount+0x581/0x30e0 fs/namespace.c:2848 ksys_mount+0x12d/0x140 fs/namespace.c:3064 __do_sys_mount fs/namespace.c:3078 [inline] __se_sys_mount fs/namespace.c:3075 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 4581: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xd9/0x260 mm/slab.c:3813 p9_fd_close+0x416/0x5b0 net/9p/trans_fd.c:893 p9_client_create+0xa9a/0x1770 net/9p/client.c:1077 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135 mount_fs+0xae/0x328 fs/super.c:1277 vfs_kern_mount.part.34+0xdc/0x4e0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:1027 [inline] do_new_mount fs/namespace.c:2518 [inline] do_mount+0x581/0x30e0 fs/namespace.c:2848 ksys_mount+0x12d/0x140 fs/namespace.c:3064 __do_sys_mount fs/namespace.c:3078 [inline] __se_sys_mount fs/namespace.c:3075 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801d6ddf340 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 0 bytes inside of 512-byte region [ffff8801d6ddf340, ffff8801d6ddf540) The buggy address belongs to the page: page:ffffea00075b77c0 count:1 mapcount:0 mapping:ffff8801da800940 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea0007398548 ffffea0006c59188 ffff8801da800940 raw: 0000000000000000 ffff8801d6ddf0c0 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d6ddf200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d6ddf280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff8801d6ddf300: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8801d6ddf380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d6ddf400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================