Subject: BUG: unable to handle kernel paging request in ip_mc_init_dev

From: syzbot <[email-masked]>
Date: Thu, 21 Dec 2017 07:52:02 -0800

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.

Unfortunately, I don't have any reproducer for this bug yet.

BUG: unable to handle kernel paging request at 00000050000005bc
IP: read_pnet include/net/net_namespace.h:270 [inline]
IP: dev_net include/linux/netdevice.h:2041 [inline]
IP: ip_mc_init_dev+0x12/0xc0 net/ipv4/igmp.c:1717
PGD 2135ac067 P4D 2135ac067 PUD 0
Oops: 0000 [#1] SMP
Dumping ftrace buffer:
    (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 8364 Comm: syz-executor4 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:read_pnet include/net/net_namespace.h:270 [inline]
RIP: 0010:dev_net include/linux/netdevice.h:2041 [inline]
RIP: 0010:ip_mc_init_dev+0x12/0xc0 net/ipv4/igmp.c:1717
RSP: 0018:ffffc90000e07c18 EFLAGS: 00010216
RAX: 0000005000000044 RBX: ffff8801faa1f800 RCX: ffffffff821dd35f
RDX: 0000000000006bd2 RSI: ffffc90004e88000 RDI: ffff8801faa1f800
RBP: ffffc90000e07c28 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801fa804000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f5acae18700(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000050000005bc CR3: 00000001faae0002 CR4: 00000000001606e0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
  inetdev_init+0x112/0x1c0 net/ipv4/devinet.c:270
  inetdev_event+0x517/0x5c0 net/ipv4/devinet.c:1461
  notifier_call_chain+0x41/0xc0 kernel/notifier.c:93
  __raw_notifier_call_chain kernel/notifier.c:394 [inline]
  raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
  call_netdevice_notifiers_info+0x32/0x60 net/core/dev.c:1679
  call_netdevice_notifiers net/core/dev.c:1697 [inline]
  register_netdevice+0x639/0x710 net/core/dev.c:7772
  tun_set_iff drivers/net/tun.c:2390 [inline]
  __tun_chr_ioctl+0xb62/0x1660 drivers/net/tun.c:2614
  tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:2867
  vfs_ioctl fs/ioctl.c:46 [inline]
  do_vfs_ioctl+0xaf/0x840 fs/ioctl.c:686
  SYSC_ioctl fs/ioctl.c:701 [inline]
  SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
  entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a09
RSP: 002b:00007f5acae17c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452a09
RDX: 00000000204c8fd8 RSI: 00000000400454ca RDI: 0000000000000013
RBP: 0000000000000088 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006edd60
R13: 00000000ffffffff R14: 00007f5acae186d4 R15: 0000000000000000
Code: 48 c7 c7 90 cf e5 82 e8 05 05 06 ff e8 9d e3 3c 00 e9 81 fe ff ff 0f  
1f 00 55 48 89 e5 41 54 53 48 89 fb e8 e1 cf 0d ff 48 8b 03 <4c> 8b a0 78  
05 00 00 e8 c2 c7 f0 ff 85 c0 74 75 e8 c9 cf 0d ff
RIP: read_pnet include/net/net_namespace.h:270 [inline] RSP:  
ffffc90000e07c18
RIP: dev_net include/linux/netdevice.h:2041 [inline] RSP: ffffc90000e07c18
RIP: ip_mc_init_dev+0x12/0xc0 net/ipv4/igmp.c:1717 RSP: ffffc90000e07c18
CR2: 00000050000005bc
---[ end trace 88e69afd99fcdbfc ]---

---
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