general protection fault, probably for non-canonical address 0xdffffc000000005b: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x00000000000002d8-0x00000000000002df] CPU: 0 PID: 6783 Comm: syz.3.2223 Tainted: G W 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 0e 6f 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 e0 6e bf fd 48 8b 1b 48 85 db 74 68 RSP: 0018:ffffc900013c70d8 EFLAGS: 00010202 RAX: 000000000000005b RBX: 00000000000002d8 RCX: dffffc0000000000 RDX: ffff8881307e8000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900013c7148 R08: dffffc0000000000 R09: ffffc900013c7340 R10: fffff52000278e6e R11: 1ffff92000278e68 R12: ffff88812f0cd300 R13: 0000000000000000 R14: 0000000000000000 R15: ffff8881125a5390 FS: 00007fcf094676c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c29a1e1 CR3: 00000001154ce000 CR4: 00000000003506b0 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+0x49e/0x20e0 net/ipv4/route.c:2674 ip_route_output_key_hash+0x123/0x1c0 net/ipv4/route.c:2564 __ip_route_output_key include/net/route.h:126 [inline] vti6_xmit net/ipv6/ip6_vti.c:463 [inline] vti6_tnl_xmit+0xc95/0x15c0 net/ipv6/ip6_vti.c:584 __netdev_start_xmit include/linux/netdevice.h:4864 [inline] netdev_start_xmit include/linux/netdevice.h:4878 [inline] xmit_one net/core/dev.c:3608 [inline] dev_hard_start_xmit+0x244/0x670 net/core/dev.c:3624 __dev_queue_xmit+0x1446/0x2540 net/core/dev.c:4210 dev_queue_xmit+0x17/0x20 net/core/dev.c:4243 __bpf_tx_skb net/core/filter.c:2129 [inline] __bpf_redirect_no_mac net/core/filter.c:2163 [inline] __bpf_redirect+0x699/0xe30 net/core/filter.c:2186 ____bpf_clone_redirect net/core/filter.c:2470 [inline] bpf_clone_redirect+0x242/0x380 net/core/filter.c:2442 bpf_prog_6893982b85ceadf7+0x56/0x6d0 bpf_dispatcher_nop_func include/linux/bpf.h:669 [inline] bpf_test_run+0x310/0x9b0 net/bpf/test_run.c:116 bpf_prog_test_run_skb+0x9c2/0x10b0 net/bpf/test_run.c:635 bpf_prog_test_run+0x350/0x3c0 kernel/bpf/syscall.c:3156 __do_sys_bpf kernel/bpf/syscall.c:4453 [inline] __se_sys_bpf+0x49f/0x680 kernel/bpf/syscall.c:4391 __x64_sys_bpf+0x7b/0x90 kernel/bpf/syscall.c:4391 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fcf0a9feba9 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:00007fcf09467038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fcf0ac45fa0 RCX: 00007fcf0a9feba9 RDX: 000000000000002c RSI: 0000200000000080 RDI: 000000000000000a RBP: 00007fcf0aa81e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcf0ac46038 R14: 00007fcf0ac45fa0 R15: 00007fffd7fe3f58 Modules linked in: ---[ end trace c145ea48e7838ed6 ]--- 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 0e 6f 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 e0 6e bf fd 48 8b 1b 48 85 db 74 68 RSP: 0018:ffffc900013c70d8 EFLAGS: 00010202 RAX: 000000000000005b RBX: 00000000000002d8 RCX: dffffc0000000000 RDX: ffff8881307e8000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900013c7148 R08: dffffc0000000000 R09: ffffc900013c7340 R10: fffff52000278e6e R11: 1ffff92000278e68 R12: ffff88812f0cd300 R13: 0000000000000000 R14: 0000000000000000 R15: ffff8881125a5390 FS: 00007fcf094676c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c29a1e1 CR3: 00000001154ce000 CR4: 00000000003506b0 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 0e 6f bf fd call 0xfdbf6f18 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 e0 6e bf fd call 0xfdbf6f18 38: 48 8b 1b mov (%rbx),%rbx 3b: 48 85 db test %rbx,%rbx 3e: 74 68 je 0xa8