From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752474AbeAZXrc (ORCPT ); Fri, 26 Jan 2018 18:47:32 -0500 Received: from mail-io0-f193.google.com ([209.85.223.193]:46797 "EHLO mail-io0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752329AbeAZXra (ORCPT ); Fri, 26 Jan 2018 18:47:30 -0500 X-Google-Smtp-Source: AH8x224rziG3q023RxBzvK8osBywHc/MaVVu6MlwFMkehX+FIld4ixObGlS8mpXZybD7NlJ3MI0kZw== Date: Fri, 26 Jan 2018 15:47:27 -0800 From: Eric Biggers To: syzbot Cc: adobriyan@gmail.com, akinobu.mita@gmail.com, akpm@linux-foundation.org, dvyukov@google.com, ebiederm@xmission.com, jpoimboe@redhat.com, linux-kernel@vger.kernel.org, mingo@kernel.org, sfr@canb.auug.org.au, syzkaller-bugs@googlegroups.com, vegard.nossum@oracle.com Subject: Re: BUG: unable to handle kernel NULL pointer dereference in proc_flush_task Message-ID: <20180126234727.zrsp354iiilo6ci3@gmail.com> References: <94eb2c03c9bc1fc2570560c0d167@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <94eb2c03c9bc1fc2570560c0d167@google.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 19, 2017 at 11:49:02PM -0800, syzbot wrote: > Hello, > > syzkaller hit the following crash on > 6084b576dca2e898f5c101baef151f7bfdbb606d > git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached > Raw console output is attached. > > syzkaller reproducer is attached. See https://goo.gl/kgGztJ > for information about syzkaller reproducers > > > BUG: unable to handle kernel NULL pointer dereference at (null) > IP: proc_flush_task_mnt fs/proc/base.c:3056 [inline] > IP: proc_flush_task+0x8a/0x1c0 fs/proc/base.c:3128 > PGD 214dd0067 P4D 214dd0067 PUD 2137d6067 PMD 0 > Oops: 0000 [#1] SMP > Dumping ftrace buffer: > (ftrace buffer empty) > Modules linked in: > CPU: 0 PID: 3142 Comm: syz-executor3 Not tainted 4.15.0-rc3-next-20171214+ > #67 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:proc_flush_task_mnt fs/proc/base.c:3056 [inline] > RIP: 0010:proc_flush_task+0x8a/0x1c0 fs/proc/base.c:3128 > RSP: 0018:ffffc9000189bc30 EFLAGS: 00010282 > RAX: 0000000000000001 RBX: 0000000000000002 RCX: ffffffff825bf264 > RDX: 0000000000000000 RSI: ffffc9000189bc58 RDI: ffffc9000189bc4d > RBP: ffffc9000189bc90 R08: 0000000000000000 R09: 0000000000000002 > R10: ffffc9000189bad8 R11: 0000000000000002 R12: ffffc9000189bc4d > R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000004 > FS: 0000000001470940(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000000 CR3: 0000000213771003 CR4: 00000000001606f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > release_task+0xf4/0x750 kernel/exit.c:195 > wait_task_zombie kernel/exit.c:1165 [inline] > wait_consider_task+0xe83/0xfb0 kernel/exit.c:1392 > do_wait_thread kernel/exit.c:1455 [inline] > do_wait+0x189/0x3d0 kernel/exit.c:1526 > kernel_wait4+0xac/0x170 kernel/exit.c:1669 > SYSC_wait4+0xb0/0xc0 kernel/exit.c:1681 > SyS_wait4+0x2c/0x40 kernel/exit.c:1677 > entry_SYSCALL_64_fastpath+0x1f/0x96 > RIP: 0033:0x40cdba > RSP: 002b:00007fff9cfdb6b8 EFLAGS: 00000246 ORIG_RAX: 000000000000003d > RAX: ffffffffffffffda RBX: 0000000001470914 RCX: 000000000040cdba > RDX: 0000000040000001 RSI: 00007fff9cfdb6dc RDI: ffffffffffffffff > RBP: 00000000000024a9 R08: 0000000000000001 R09: 0000000001470940 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000024a9 > R13: 000000000000001f R14: 000000000002eceb R15: 0000000000000001 > Code: d0 48 c1 e2 04 44 8b 3c 11 48 c7 c2 ec d7 f5 82 44 8b 68 30 48 8b 40 > 38 4c 8b 70 58 44 89 e9 e8 dd 83 10 01 89 45 cc 48 8d 75 c8 <49> 8b 3e e8 6e > 9d f7 ff 48 85 c0 48 89 45 a8 74 1d e8 60 2d e0 > RIP: proc_flush_task_mnt fs/proc/base.c:3056 [inline] RSP: ffffc9000189bc30 > RIP: proc_flush_task+0x8a/0x1c0 fs/proc/base.c:3128 RSP: ffffc9000189bc30 > CR2: 0000000000000000 > ---[ end trace 96968f6879f5e625 ]--- > > > --- > This bug is generated by a dumb bot. It may contain errors. > See https://goo.gl/tpsmEJ for details. > Direct all questions to syzkaller@googlegroups.com. > Please credit me with: Reported-by: syzbot > > syzbot will keep track of this bug report. > Once a fix for this bug is merged into any tree, reply to this email with: > #syz fix: exact-commit-title #syz fix: pid: Handle failure to allocate the first pid in a pid namespace