From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f197.google.com ([209.85.223.197]:45654 "EHLO mail-io0-f197.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932889AbeF2FiC (ORCPT ); Fri, 29 Jun 2018 01:38:02 -0400 Received: by mail-io0-f197.google.com with SMTP id i18-v6so5994155iog.12 for ; Thu, 28 Jun 2018 22:38:01 -0700 (PDT) MIME-Version: 1.0 Date: Thu, 28 Jun 2018 22:38:01 -0700 Message-ID: <0000000000004a5d64056fc140c0@google.com> Subject: BUG: unable to handle kernel NULL pointer dereference in ep_item_poll From: syzbot To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Hello, syzbot found the following crash on: HEAD commit: 90368a37fbbe Merge tag 'printk-for-4.18-rc3' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14e0dd14400000 kernel config: https://syzkaller.appspot.com/x/.config?x=a63be0c83e84d370 dashboard link: https://syzkaller.appspot.com/bug?extid=57727883dbad76db2ef0 compiler: gcc (GCC) 8.0.1 20180413 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+57727883dbad76db2ef0@syzkaller.appspotmail.com device lo entered promiscuous mode device lo left promiscuous mode BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 PGD 1ccf13067 P4D 1ccf13067 PUD 1bc558067 PMD 0 Oops: 0010 [#1] SMP KASAN CPU: 1 PID: 13288 Comm: syz-executor0 Not tainted 4.18.0-rc2+ #121 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010: (null) Code: Bad RIP value. RSP: 0018:ffff8801ce74f568 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8801b2a681c0 RCX: ffffc90001e14000 RDX: ffff8801ce74f7c0 RSI: ffff8801b2a681c0 RDI: ffff8801b819ed00 RBP: ffff8801ce74f610 R08: ffff8801cfc64480 R09: ffffed003b5e46d6 R10: ffffed003b5e46d6 R11: ffff8801daf236b3 R12: ffff8801ce74f7c0 R13: ffff8801b819ed00 R14: ffffffff8818a920 R15: ffff8801cfd33740 FS: 00007f1c1e46f700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001ca482000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vfs_poll include/linux/poll.h:86 [inline] ep_item_poll.isra.14+0x15c/0x400 fs/eventpoll.c:887 ep_insert+0x6c1/0x1c20 fs/eventpoll.c:1459 __do_sys_epoll_ctl fs/eventpoll.c:2113 [inline] __se_sys_epoll_ctl fs/eventpoll.c:1999 [inline] __x64_sys_epoll_ctl+0xf00/0x10a0 fs/eventpoll.c:1999 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455a99 Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f1c1e46ec68 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9 RAX: ffffffffffffffda RBX: 00007f1c1e46f6d4 RCX: 0000000000455a99 RDX: 0000000000000013 RSI: 0000000000000001 RDI: 0000000000000014 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000020000180 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004bb9c5 R14: 00000000004c8910 R15: 0000000000000000 Modules linked in: Dumping ftrace buffer: (ftrace buffer empty) CR2: 0000000000000000 ---[ end trace 727efc30ae8b7e22 ]--- RIP: 0010: (null) Code: Bad RIP value. RSP: 0018:ffff8801ce74f568 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8801b2a681c0 RCX: ffffc90001e14000 RDX: ffff8801ce74f7c0 RSI: ffff8801b2a681c0 RDI: ffff8801b819ed00 RBP: ffff8801ce74f610 R08: ffff8801cfc64480 R09: ffffed003b5e46d6 R10: ffffed003b5e46d6 R11: ffff8801daf236b3 R12: ffff8801ce74f7c0 R13: ffff8801b819ed00 R14: ffffffff8818a920 R15: ffff8801cfd33740 FS: 00007f1c1e46f700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 00000001ca482000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot.