general protection fault, probably for non-canonical address 0xdffffc000000005a: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x00000000000002d0-0x00000000000002d7] CPU: 1 PID: 16130 Comm: syz.1.4559 Tainted: G W 6.1.145-syzkaller-00002-gc750dc582629 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:ip_ignore_linkdown include/linux/inetdevice.h:259 [inline] RIP: 0010:fib_lookup_good_nhc net/ipv4/fib_trie.c:1413 [inline] RIP: 0010:nexthop_get_nhc_lookup+0x17e/0x750 include/net/nexthop.h:405 Code: d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 78 15 7c fd 48 89 5d a8 48 8b 1b b8 d0 02 00 00 48 01 c3 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 53 15 7c fd 48 8b 1b 48 85 db 0f RSP: 0018:ffffc90000bd6d58 EFLAGS: 00010206 RAX: 000000000000005a RBX: 00000000000002d0 RCX: 0000000000000002 RDX: ffff8881158e6540 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000bd6dc8 R08: ffff8881158e6540 R09: 0000000000000003 R10: 0000000000000008 R11: 0000000000000002 R12: ffff88811ea90200 R13: dffffc0000000000 R14: 0000000000000000 R15: ffffc90000bd7280 FS: 00007fefd03e26c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2d71fff8 CR3: 0000000131f03000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 00000000000004ce DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: fib_table_lookup+0x10b7/0x1a60 net/ipv4/fib_trie.c:1590 fib4_rule_action+0x115/0x1a0 net/ipv4/fib_rules.c:136 fib_rules_lookup+0x4ae/0x900 net/core/fib_rules.c:318 __fib_lookup+0xe4/0x150 net/ipv4/fib_rules.c:93 fib_lookup include/net/ip_fib.h:376 [inline] __fib_validate_source net/ipv4/fib_frontend.c:378 [inline] fib_validate_source+0x79f/0x1200 net/ipv4/fib_frontend.c:451 ip_route_input_slow net/ipv4/route.c:2349 [inline] ip_route_input_rcu+0x1c8a/0x2580 net/ipv4/route.c:2511 ip_route_input_noref+0xbb/0x110 net/ipv4/route.c:2522 ip_rcv_finish_core+0x4b0/0x1490 net/ipv4/ip_input.c:365 ip_rcv_finish net/ipv4/ip_input.c:447 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ip_rcv+0xe0/0x270 net/ipv4/ip_input.c:569 __netif_receive_skb_one_core net/core/dev.c:5585 [inline] __netif_receive_skb+0xd7/0x2a0 net/core/dev.c:5699 netif_receive_skb_internal net/core/dev.c:5785 [inline] netif_receive_skb+0x98/0x3d0 net/core/dev.c:5844 tun_rx_batched+0x1b6/0x770 drivers/net/tun.c:1548 tun_get_user+0x2494/0x3320 drivers/net/tun.c:1998 tun_chr_write_iter+0x1fb/0x300 drivers/net/tun.c:2044 call_write_iter include/linux/fs.h:2282 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x5db/0xca0 fs/read_write.c:584 ksys_write+0x140/0x240 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __x64_sys_write+0x7b/0x90 fs/read_write.c:646 x64_sys_call+0x27b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fefcf58d69f Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48 RSP: 002b:00007fefd03e2000 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fefcf7b6180 RCX: 00007fefcf58d69f RDX: 0000000000000036 RSI: 0000200000000140 RDI: 00000000000000c8 RBP: 00007fefcf611e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000036 R11: 0000000000000293 R12: 0000000000000000 R13: 00007fefcf7b6218 R14: 00007fefcf7b6180 R15: 00007ffc5ab03e38 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:ip_ignore_linkdown include/linux/inetdevice.h:259 [inline] RIP: 0010:fib_lookup_good_nhc net/ipv4/fib_trie.c:1413 [inline] RIP: 0010:nexthop_get_nhc_lookup+0x17e/0x750 include/net/nexthop.h:405 Code: d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 78 15 7c fd 48 89 5d a8 48 8b 1b b8 d0 02 00 00 48 01 c3 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 53 15 7c fd 48 8b 1b 48 85 db 0f RSP: 0018:ffffc90000bd6d58 EFLAGS: 00010206 RAX: 000000000000005a RBX: 00000000000002d0 RCX: 0000000000000002 RDX: ffff8881158e6540 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000bd6dc8 R08: ffff8881158e6540 R09: 0000000000000003 R10: 0000000000000008 R11: 0000000000000002 R12: ffff88811ea90200 R13: dffffc0000000000 R14: 0000000000000000 R15: ffffc90000bd7280 FS: 00007fefd03e26c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2d71fff8 CR3: 0000000131f03000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 00000000000004ce DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: d8 48 c1 fmuls -0x3f(%rax) 3: e8 03 42 80 3c call 0x3c80420b 8: 28 00 sub %al,(%rax) a: 74 08 je 0x14 c: 48 89 df mov %rbx,%rdi f: e8 78 15 7c fd call 0xfd7c158c 14: 48 89 5d a8 mov %rbx,-0x58(%rbp) 18: 48 8b 1b mov (%rbx),%rbx 1b: b8 d0 02 00 00 mov $0x2d0,%eax 20: 48 01 c3 add %rax,%rbx 23: 48 89 d8 mov %rbx,%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: 48 89 df mov %rbx,%rdi 34: e8 53 15 7c fd call 0xfd7c158c 39: 48 8b 1b mov (%rbx),%rbx 3c: 48 85 db test %rbx,%rbx 3f: 0f .byte 0xf