general protection fault in nexthop_is_blackhole

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    c3d8f220 Merge tag 'kbuild-fixes-v5.9' of git://git.kernel..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11c48c96900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bb68b9e8a8cc842f
dashboard link: https://syzkaller.appspot.com/bug?extid=b2c08a2f5cfef635cc3a
compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d75e39900000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12aea519900000

The issue was bisected to:

commit de47c5d8e11dda678e4354eeb4235e58e92f7cd2
Author: Hariprasad Kelam <hariprasad.kelam@xxxxxxxxx>
Date:   Sat Jun 8 09:00:50 2019 +0000

    af_key: make use of BUG_ON macro

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=10450972900000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=12450972900000
console output: https://syzkaller.appspot.com/x/log.txt?x=14450972900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b2c08a2f5cfef635cc3a@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: de47c5d8e11d ("af_key: make use of BUG_ON macro")

IPv6: RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE
IPv6: NLM_F_CREATE should be set when creating new route
IPv6: NLM_F_CREATE should be set when creating new route
general protection fault, probably for non-canonical address 0xdffffc0000000010: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000080-0x0000000000000087]
CPU: 0 PID: 7050 Comm: syz-executor320 Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:nexthop_is_blackhole+0x145/0x250 include/net/nexthop.h:240
Code: 4d fa 49 83 c6 10 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 39 f0 8c fa 49 8b 1e 48 83 eb 80 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 1c f0 8c fa 48 8b 1b e8 e4 4e 02
RSP: 0018:ffffc900061172b8 EFLAGS: 00010202
RAX: 0000000000000010 RBX: 0000000000000080 RCX: ffff888091444300
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000001 R08: ffffffff8727dfc7 R09: ffffed1012299e09
R10: ffffed1012299e09 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff8880919da280 R14: ffff8880a9576610 R15: dffffc0000000000
FS:  0000000001a89880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000300 CR3: 00000000a7555000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 rt6_fill_node+0xfe9/0x1f90 net/ipv6/route.c:5584
 inet6_rt_notify+0x2ab/0x500 net/ipv6/route.c:6017
 fib6_add_rt2node net/ipv6/ip6_fib.c:1246 [inline]
 fib6_add+0x203b/0x3bd0 net/ipv6/ip6_fib.c:1473
 __ip6_ins_rt net/ipv6/route.c:1317 [inline]
 ip6_route_add+0x84/0x120 net/ipv6/route.c:3744
 inet6_rtm_newroute+0x22f/0x2150 net/ipv6/route.c:5360
 rtnetlink_rcv_msg+0x889/0xd40 net/core/rtnetlink.c:5563
 netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2470
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0xa57/0xd70 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 ____sys_sendmsg+0x519/0x800 net/socket.c:2353
 ___sys_sendmsg net/socket.c:2407 [inline]
 __sys_sendmsg+0x2b1/0x360 net/socket.c:2440
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x443ef9
Code: e8 8c 07 03 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 bb 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd64ccd428 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000443ef9
RDX: 0000000000000000 RSI: 0000000020000300 RDI: 0000000000000003
RBP: 00007ffd64ccd430 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000b6f1
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace e62dc7d3de715e59 ]---
RIP: 0010:nexthop_is_blackhole+0x145/0x250 include/net/nexthop.h:240
Code: 4d fa 49 83 c6 10 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 39 f0 8c fa 49 8b 1e 48 83 eb 80 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 1c f0 8c fa 48 8b 1b e8 e4 4e 02
RSP: 0018:ffffc900061172b8 EFLAGS: 00010202
RAX: 0000000000000010 RBX: 0000000000000080 RCX: ffff888091444300
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000001 R08: ffffffff8727dfc7 R09: ffffed1012299e09
R10: ffffed1012299e09 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff8880919da280 R14: ffff8880a9576610 R15: dffffc0000000000
FS:  0000000001a89880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000300 CR3: 00000000a7555000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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