Oops: general protection fault, probably for non-canonical address 0xdffffc0000000083: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000418-0x000000000000041f] CPU: 1 UID: 0 PID: 15541 Comm: syz.4.2086 Not tainted 6.16.0-next-20250807-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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 4b e2 19 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 2c e2 19 f8 4d 8b 24 24 e8 f3 a1 RSP: 0018:ffffc90003ddf1d0 EFLAGS: 00010202 RAX: 0000000000000083 RBX: ffff888027543020 RCX: 0000000000000002 RDX: ffff88802cd15a00 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff888027543037 R08: 0000000000000000 R09: ffffffff8a0f31bf R10: 0000000000000008 R11: 0000000000000002 R12: 0000000000000418 R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff11004ea8606 FS: 00007f6ce80786c0(0000) GS:ffff888125d16000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33519ff8 CR3: 0000000062f78000 CR4: 00000000003526f0 DR0: 000000000000004b DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: nexthop_get_nhc_lookup+0x1af/0x400 include/net/nexthop.h:437 fib_table_lookup+0xf26/0x16e0 net/ipv4/fib_trie.c:1584 fib4_rule_action+0x1fb/0x330 net/ipv4/fib_rules.c:138 fib_rules_lookup+0x8a6/0xe90 net/core/fib_rules.c:339 __fib_lookup+0xf9/0x200 net/ipv4/fib_rules.c:95 ip_route_output_key_hash_rcu+0x31b/0x23d0 net/ipv4/route.c:2805 ip_route_output_key_hash+0x1b9/0x2e0 net/ipv4/route.c:2696 __ip_route_output_key include/net/route.h:169 [inline] ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2923 ip_route_output_key include/net/route.h:179 [inline] sctp_v4_get_dst+0x3c7/0x1200 net/sctp/protocol.c:454 sctp_transport_route+0x115/0x2f0 net/sctp/transport.c:457 sctp_assoc_add_peer+0x657/0x13b0 net/sctp/associola.c:663 sctp_connect_new_asoc+0x30a/0x690 net/sctp/socket.c:1100 __sctp_connect+0x5ba/0xd50 net/sctp/socket.c:1198 __sctp_setsockopt_connectx net/sctp/socket.c:1337 [inline] sctp_getsockopt_connectx3+0x2c4/0x440 net/sctp/socket.c:1422 sctp_getsockopt+0x98a/0xb60 net/sctp/socket.c:8134 do_sock_getsockopt+0x36f/0x450 net/socket.c:2405 __sys_getsockopt net/socket.c:2434 [inline] __do_sys_getsockopt net/socket.c:2441 [inline] __se_sys_getsockopt net/socket.c:2438 [inline] __x64_sys_getsockopt+0x1a5/0x250 net/socket.c:2438 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6ce718ebe9 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:00007f6ce8078038 EFLAGS: 00000246 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 00007f6ce73b6180 RCX: 00007f6ce718ebe9 RDX: 000000000000006f RSI: 0000000000000084 RDI: 0000000000000009 RBP: 00007f6ce7211e19 R08: 0000200000000180 R09: 0000000000000000 R10: 0000200000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6ce73b6218 R14: 00007f6ce73b6180 R15: 00007ffe22badcb8 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 4b e2 19 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 2c e2 19 f8 4d 8b 24 24 e8 f3 a1 RSP: 0018:ffffc90003ddf1d0 EFLAGS: 00010202 RAX: 0000000000000083 RBX: ffff888027543020 RCX: 0000000000000002 RDX: ffff88802cd15a00 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff888027543037 R08: 0000000000000000 R09: ffffffff8a0f31bf R10: 0000000000000008 R11: 0000000000000002 R12: 0000000000000418 R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff11004ea8606 FS: 00007f6ce80786c0(0000) GS:ffff888125d16000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6ce8035f98 CR3: 0000000062f78000 CR4: 00000000003526f0 DR0: 000000000000004b DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 ---------------- 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 4b e2 19 f8 call 0xf819e265 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 2c e2 19 f8 call 0xf819e265 39: 4d 8b 24 24 mov (%r12),%r12 3d: e8 .byte 0xe8 3e: f3 repz 3f: a1 .byte 0xa1