Oops: general protection fault, probably for non-canonical address 0xdffffc0000000083: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000418-0x000000000000041f]
CPU: 0 UID: 0 PID: 25916 Comm: syz.0.4154 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:ip_ignore_linkdown include/linux/inetdevice.h:270 [inline]
RIP: 0010:fib_lookup_good_nhc+0x85/0x3d0 net/ipv4/fib_trie.c:1408
Code: 4c 89 24 24 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 0b 92 1a f8 41 bc 18 04 00 00 4c 03 23 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 ec 91 1a f8 4d 8b 24 24 e8 c3 c0
RSP: 0018:ffffc9000b6ef8b8 EFLAGS: 00010202
RAX: 0000000000000083 RBX: ffff888025146420 RCX: 0000000000000002
RDX: ffff88802bc7bc00 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff888025146437 R08: 0000000000000000 R09: ffffffff89e9c626
R10: ffffc9000b6efb80 R11: fffff520016ddf76 R12: 0000000000000418
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff11004a28c86
FS:  0000000000000000(0000) GS:ffff888125c15000(0063) knlGS:00000000f544cb40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000002eb18ffc CR3: 000000005cf7c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 nexthop_get_nhc_lookup+0x1af/0x400 include/net/nexthop.h:437
 fib_table_lookup+0xf26/0x16e0 net/ipv4/fib_trie.c:1584
 fib_lookup+0x1c5/0x440 include/net/ip_fib.h:390
 ip_route_output_key_hash_rcu+0x31b/0x23e0 net/ipv4/route.c:2809
 ip_route_output_key_hash+0x1b9/0x2e0 net/ipv4/route.c:2700
 __ip_route_output_key include/net/route.h:169 [inline]
 ip_route_connect include/net/route.h:348 [inline]
 __ip4_datagram_connect+0x8f4/0x1270 net/ipv4/datagram.c:49
 udp_connect+0x33/0x1f0 net/ipv4/udp.c:2153
 __sys_connect_file net/socket.c:2086 [inline]
 __sys_connect+0x313/0x440 net/socket.c:2105
 __do_sys_connect net/socket.c:2111 [inline]
 __se_sys_connect net/socket.c:2108 [inline]
 __ia32_sys_connect+0x7a/0x90 net/socket.c:2108
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xb6/0x2b0 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf709e539
Code: 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f544c55c EFLAGS: 00000206 ORIG_RAX: 000000000000016a
RAX: ffffffffffffffda RBX: 000000000000000d RCX: 0000000080000480
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ip_ignore_linkdown include/linux/inetdevice.h:270 [inline]
RIP: 0010:fib_lookup_good_nhc+0x85/0x3d0 net/ipv4/fib_trie.c:1408
Code: 4c 89 24 24 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 0b 92 1a f8 41 bc 18 04 00 00 4c 03 23 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 ec 91 1a f8 4d 8b 24 24 e8 c3 c0
RSP: 0018:ffffc9000b6ef8b8 EFLAGS: 00010202
RAX: 0000000000000083 RBX: ffff888025146420 RCX: 0000000000000002
RDX: ffff88802bc7bc00 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff888025146437 R08: 0000000000000000 R09: ffffffff89e9c626
R10: ffffc9000b6efb80 R11: fffff520016ddf76 R12: 0000000000000418
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff11004a28c86
FS:  0000000000000000(0000) GS:ffff888125c15000(0063) knlGS:00000000f544cb40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000008012b018 CR3: 000000005cf7c000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	4c 89 24 24          	mov    %r12,(%rsp)
   4:	48 89 d8             	mov    %rbx,%rax
   7:	48 c1 e8 03          	shr    $0x3,%rax
   b:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
  10:	74 08                	je     0x1a
  12:	48 89 df             	mov    %rbx,%rdi
  15:	e8 0b 92 1a f8       	call   0xf81a9225
  1a:	41 bc 18 04 00 00    	mov    $0x418,%r12d
  20:	4c 03 23             	add    (%rbx),%r12
  23:	4c 89 e0             	mov    %r12,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 e7             	mov    %r12,%rdi
  34:	e8 ec 91 1a f8       	call   0xf81a9225
  39:	4d 8b 24 24          	mov    (%r12),%r12
  3d:	e8                   	.byte 0xe8
  3e:	c3                   	ret
  3f:	c0                   	.byte 0xc0