Subject: BUG: unable to handle kernel paging request in __ipv6_dev_get_saddr

From: syzbot <[email-masked]>
Date: Sun, 17 Dec 2017 21:53:01 -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 ffffffffffffff24
IP: __ipv6_dev_get_saddr+0x6f/0x190 net/ipv6/addrconf.c:1616
PGD 3021067 P4D 3021067 PUD 3023067 PMD 0
Oops: 0000 [#1] SMP
Dumping ftrace buffer:
    (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 4857 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:__ipv6_dev_get_saddr+0x6f/0x190 net/ipv6/addrconf.c:1616
RSP: 0018:ffffc90000d6fb68 EFLAGS: 00010216
RAX: 0000000000010000 RBX: fffffffffffffec8 RCX: ffffffff8224b08f
RDX: 00000000000001c7 RSI: ffffc90004e80000 RDI: ffff8801e2922200
RBP: ffffc90000d6fba8 R08: 0000000000000000 R09: 0000000000000002
R10: ffffc90000d6fb40 R11: 0000000000000002 R12: ffff8801e2939400
R13: ffffc90000d6fc00 R14: ffff8801e2922200 R15: ffffc90000d6fbc8
FS:  00007f768e222700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffff24 CR3: 00000001e38d4002 CR4: 00000000001606f0
DR0: 0000000020000000 DR1: 0000000000000004 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
  ipv6_dev_get_saddr+0x255/0x3d0 net/ipv6/addrconf.c:1771
  ip6_route_get_saddr include/net/ip6_route.h:116 [inline]
  ip6_dst_lookup_tail+0x11a/0x330 net/ipv6/ip6_output.c:955
  ip6_dst_lookup_flow+0x3b/0xa0 net/ipv6/ip6_output.c:1076
  ip6_datagram_dst_update+0x21b/0x670 net/ipv6/datagram.c:91
  __ip6_datagram_connect+0x1c6/0x3f0 net/ipv6/datagram.c:252
  ip6_datagram_connect+0x2f/0x50 net/ipv6/datagram.c:274
  inet_dgram_connect+0x78/0xb0 net/ipv4/af_inet.c:541
  SYSC_connect+0xaf/0x130 net/socket.c:1619
  SyS_connect+0x24/0x30 net/socket.c:1600
  entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a09
RSP: 002b:00007f768e221c58 EFLAGS: 00000212 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452a09
RDX: 000000000000001c RSI: 0000000020e91fe4 RDI: 0000000000000013
RBP: 000000000000053c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f4e40
R13: 00000000ffffffff R14: 00007f768e2226d4 R15: 0000000000000000
Code: 63 ed 48 89 45 c8 49 8b 44 24 08 49 c1 e5 05 49 01 dd 48 8d 98 c8 fe  
ff ff 48 39 c6 49 89 5d 08 0f 84 c1 00 00 00 e8 b1 f2 06 ff <8b> 43 5c 83  
e0 44 83 f8 40 0f 84 83 00 00 00 e8 9d f2 06 ff 48
RIP: __ipv6_dev_get_saddr+0x6f/0x190 net/ipv6/addrconf.c:1616 RSP:  
ffffc90000d6fb68
CR2: ffffffffffffff24
---[ end trace 32a93ed782cead93 ]---

---
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