syzbot

netlink: 8 bytes leftover after parsing attributes in process `syz.0.4405'.
general protection fault, probably for non-canonical address 0xdffffc000000005c: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000002e0-0x00000000000002e7]
CPU: 1 PID: 15191 Comm: syz.0.4405 Not tainted 5.10.238-syzkaller-00282-gd76d4cd0623a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__in6_dev_get include/net/addrconf.h:343 [inline]
RIP: 0010:ip6_ignore_linkdown include/net/addrconf.h:434 [inline]
RIP: 0010:find_match+0xa7/0xd60 net/ipv6/route.c:739
Code: 41 80 7c 05 00 00 74 08 4c 89 f7 e8 73 70 a9 fd 41 bc e0 02 00 00 4d 03 26 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 e7 e8 4b 70 a9 fd 4d 8b 24 24 4d 85 e4 0f
RSP: 0018:ffffc90000d671b0 EFLAGS: 00010206
RAX: 000000000000005c RBX: 0000000000000041 RCX: dffffc0000000000
RDX: ffff888119ad93c0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000d67238 R08: ffffc90000d67560 R09: ffffc90000d67570
R10: fffff520001acedb R11: 1ffff920001aced9 R12: 00000000000002e0
R13: 1ffff11021031b24 R14: ffff88810818d920 R15: 0000000000000000
FS:  00007fe4b04456c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000004380 CR3: 00000001269d0000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 rt6_nh_find_match+0xd9/0x140 net/ipv6/route.c:779
 nexthop_for_each_fib6_nh+0xf6/0x1e0 net/ipv4/nexthop.c:602
 __find_rr_leaf+0x50f/0x900 net/ipv6/route.c:820
 find_rr_leaf net/ipv6/route.c:848 [inline]
 rt6_select net/ipv6/route.c:892 [inline]
 fib6_table_lookup+0x2f4/0x9f0 net/ipv6/route.c:2190
 ip6_nh_lookup_table net/ipv6/route.c:3245 [inline]
 ip6_route_check_nh net/ipv6/route.c:3288 [inline]
 ip6_validate_gw net/ipv6/route.c:3372 [inline]
 fib6_nh_init+0xdb6/0x1de0 net/ipv6/route.c:3488
 ip6_route_info_create+0xa02/0x1490 net/ipv6/route.c:3725
 ip6_route_add+0x27/0x130 net/ipv6/route.c:3769
 ipv6_route_ioctl+0x328/0x420 net/ipv6/route.c:4372
 inet6_ioctl+0x1e4/0x240 net/ipv6/af_inet6.c:581
 sock_do_ioctl+0xd9/0x330 net/socket.c:1067
 sock_ioctl+0x504/0x710 net/socket.c:1207
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0x121/0x1a0 fs/ioctl.c:739
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fe4b1ddc929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe4b0445038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe4b2003fa0 RCX: 00007fe4b1ddc929
RDX: 0000200000000140 RSI: 000000000000890b RDI: 0000000000000006
RBP: 00007fe4b1e5eb39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe4b2003fa0 R15: 00007ffd3e9fbbf8
Modules linked in:
---[ end trace f2894983347a70a0 ]---
RIP: 0010:__in6_dev_get include/net/addrconf.h:343 [inline]
RIP: 0010:ip6_ignore_linkdown include/net/addrconf.h:434 [inline]
RIP: 0010:find_match+0xa7/0xd60 net/ipv6/route.c:739
Code: 41 80 7c 05 00 00 74 08 4c 89 f7 e8 73 70 a9 fd 41 bc e0 02 00 00 4d 03 26 4c 89 e0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 e7 e8 4b 70 a9 fd 4d 8b 24 24 4d 85 e4 0f
RSP: 0018:ffffc90000d671b0 EFLAGS: 00010206
RAX: 000000000000005c RBX: 0000000000000041 RCX: dffffc0000000000
RDX: ffff888119ad93c0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000d67238 R08: ffffc90000d67560 R09: ffffc90000d67570
R10: fffff520001acedb R11: 1ffff920001aced9 R12: 00000000000002e0
R13: 1ffff11021031b24 R14: ffff88810818d920 R15: 0000000000000000
FS:  00007fe4b04456c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000aab030 CR3: 00000001269d0000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	41 80 7c 05 00 00    	cmpb   $0x0,0x0(%r13,%rax,1)
   6:	74 08                	je     0x10
   8:	4c 89 f7             	mov    %r14,%rdi
   b:	e8 73 70 a9 fd       	call   0xfda97083
  10:	41 bc e0 02 00 00    	mov    $0x2e0,%r12d
  16:	4d 03 26             	add    (%r14),%r12
  19:	4c 89 e0             	mov    %r12,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 e7             	mov    %r12,%rdi
  33:	e8 4b 70 a9 fd       	call   0xfda97083
  38:	4d 8b 24 24          	mov    (%r12),%r12
  3c:	4d 85 e4             	test   %r12,%r12
  3f:	0f                   	.byte 0xf