general protection fault, probably for non-canonical address 0xdffffc000000005b: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x00000000000002d8-0x00000000000002df] CPU: 1 PID: 24752 Comm: syz.9.6420 Tainted: G W 5.10.240-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025 RIP: 0010:ip_ignore_linkdown include/linux/inetdevice.h:254 [inline] RIP: 0010:fib_lookup_good_nhc net/ipv4/fib_trie.c:1363 [inline] RIP: 0010:nexthop_get_nhc_lookup+0x1a2/0x6c0 include/net/nexthop.h:291 Code: 74 08 48 89 df e8 5e aa bf fd 48 89 5d a8 48 8b 1b b8 d8 02 00 00 48 01 c3 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 30 aa bf fd 48 8b 1b 48 85 db 74 68 RSP: 0018:ffffc90000fb75c0 EFLAGS: 00010202 RAX: 000000000000005b RBX: 00000000000002d8 RCX: dffffc0000000000 RDX: ffff88812889e2c0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000fb7630 R08: dffffc0000000000 R09: ffffc90000fb7820 R10: fffff520001f6f0a R11: 1ffff920001f6f04 R12: ffff888117171400 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88810b5dcf90 FS: 00007fa176c2c6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2dd19ff8 CR3: 000000010f4d1000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: fib_table_lookup+0xe4c/0x1730 net/ipv4/fib_trie.c:1542 fib_lookup include/net/ip_fib.h:379 [inline] ip_route_output_key_hash_rcu+0x477/0x2060 net/ipv4/route.c:2671 ip_route_output_key_hash+0x123/0x1c0 net/ipv4/route.c:2561 __ip_route_output_key include/net/route.h:126 [inline] ip_route_connect include/net/route.h:319 [inline] tcp_v4_connect+0x68c/0x1b30 net/ipv4/tcp_ipv4.c:238 tcp_v6_connect+0xa4c/0x1990 net/ipv6/tcp_ipv6.c:249 __inet_stream_connect+0x276/0xd70 net/ipv4/af_inet.c:671 inet_stream_connect+0x62/0xa0 net/ipv4/af_inet.c:735 __sys_connect_file net/socket.c:1866 [inline] __sys_connect+0x38c/0x410 net/socket.c:1883 __do_sys_connect net/socket.c:1893 [inline] __se_sys_connect net/socket.c:1890 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:1890 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fa178205be9 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:00007fa176c2c038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00007fa17843d180 RCX: 00007fa178205be9 RDX: 000000000000001c RSI: 0000200000000000 RDI: 000000000000000c RBP: 00007fa178288e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa17843d218 R14: 00007fa17843d180 R15: 00007ffdf8d87e68 Modules linked in: ---[ end trace 85b24caef13a0b1d ]--- RIP: 0010:ip_ignore_linkdown include/linux/inetdevice.h:254 [inline] RIP: 0010:fib_lookup_good_nhc net/ipv4/fib_trie.c:1363 [inline] RIP: 0010:nexthop_get_nhc_lookup+0x1a2/0x6c0 include/net/nexthop.h:291 Code: 74 08 48 89 df e8 5e aa bf fd 48 89 5d a8 48 8b 1b b8 d8 02 00 00 48 01 c3 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 30 aa bf fd 48 8b 1b 48 85 db 74 68 RSP: 0018:ffffc90000fb75c0 EFLAGS: 00010202 RAX: 000000000000005b RBX: 00000000000002d8 RCX: dffffc0000000000 RDX: ffff88812889e2c0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000fb7630 R08: dffffc0000000000 R09: ffffc90000fb7820 R10: fffff520001f6f0a R11: 1ffff920001f6f04 R12: ffff888117171400 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88810b5dcf90 FS: 00007fa176c2c6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2dd19ff8 CR3: 000000010f4d1000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 74 08 je 0xa 2: 48 89 df mov %rbx,%rdi 5: e8 5e aa bf fd call 0xfdbfaa68 a: 48 89 5d a8 mov %rbx,-0x58(%rbp) e: 48 8b 1b mov (%rbx),%rbx 11: b8 d8 02 00 00 mov $0x2d8,%eax 16: 48 01 c3 add %rax,%rbx 19: 48 89 d8 mov %rbx,%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: 48 89 df mov %rbx,%rdi 33: e8 30 aa bf fd call 0xfdbfaa68 38: 48 8b 1b mov (%rbx),%rbx 3b: 48 85 db test %rbx,%rbx 3e: 74 68 je 0xa8