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: 24293 Comm: syz.3.4477 Not tainted 6.16.0-rc5-syzkaller-00266-g3f31a806a62e #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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 fb 6f 27 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 dc 6f 27 f8 4d 8b 24 24 e8 13 0c RSP: 0018:ffffc9000cf7e710 EFLAGS: 00010202 RAX: 0000000000000083 RBX: ffff888042f62f20 RCX: 0000000000000002 RDX: ffff888057685a00 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff888042f62f37 R08: 0000000000000000 R09: ffffffff89dd5266 R10: ffffc9000cf7e9e0 R11: fffff520019efd42 R12: 0000000000000418 R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff110085ec5e6 FS: 0000000000000000(0000) GS:ffff888125c1b000(0063) knlGS:00000000f50feb40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 000000000c41b50e CR3: 000000006625a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 000000000000000e 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 fib_lookup+0x1c5/0x440 include/net/ip_fib.h:390 ip_route_output_key_hash_rcu+0x2fb/0x23a0 net/ipv4/route.c:2803 ip_route_output_key_hash+0x1b9/0x2e0 net/ipv4/route.c:2694 __ip_route_output_key include/net/route.h:169 [inline] ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2921 ip_route_output_key include/net/route.h:179 [inline] sctp_v4_get_dst+0x3c7/0x1200 net/sctp/protocol.c:454 sctp_transport_route+0x118/0x2f0 net/sctp/transport.c:457 sctp_ootb_pkt_new+0x28b/0x3c0 net/sctp/sm_statefuns.c:6435 sctp_sf_abort_violation+0x14b/0xc60 net/sctp/sm_statefuns.c:4769 sctp_sf_violation_chunklen net/sctp/sm_statefuns.c:4828 [inline] sctp_sf_ootb+0x4df/0x7c0 net/sctp/sm_statefuns.c:-1 sctp_do_sm+0x1e7/0x5a20 net/sctp/sm_sideeffect.c:1172 sctp_endpoint_bh_rcv+0x591/0x7e0 net/sctp/endpointola.c:407 sctp_rcv+0x1ca6/0x2490 net/sctp/input.c:243 ip_protocol_deliver_rcu+0x2e0/0x440 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x2fb/0x580 net/ipv4/ip_input.c:233 NF_HOOK+0x309/0x3a0 include/linux/netfilter.h:317 NF_HOOK+0x309/0x3a0 include/linux/netfilter.h:317 __netif_receive_skb_one_core net/core/dev.c:5977 [inline] __netif_receive_skb+0x143/0x380 net/core/dev.c:6090 netif_receive_skb_internal net/core/dev.c:6176 [inline] netif_receive_skb+0x1cb/0x790 net/core/dev.c:6235 tun_rx_batched+0x1b9/0x730 drivers/net/tun.c:1485 tun_get_user+0x298e/0x3ce0 drivers/net/tun.c:1938 tun_chr_write_iter+0x113/0x200 drivers/net/tun.c:1984 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x54b/0xa90 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 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: 0023:0xf710e539 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:00000000f50fe55c EFLAGS: 00000206 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000080000280 RDX: 000000000000004e RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 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 fb 6f 27 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 dc 6f 27 f8 4d 8b 24 24 e8 13 0c RSP: 0018:ffffc9000cf7e710 EFLAGS: 00010202 RAX: 0000000000000083 RBX: ffff888042f62f20 RCX: 0000000000000002 RDX: ffff888057685a00 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff888042f62f37 R08: 0000000000000000 R09: ffffffff89dd5266 R10: ffffc9000cf7e9e0 R11: fffff520019efd42 R12: 0000000000000418 R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff110085ec5e6 FS: 0000000000000000(0000) GS:ffff888125c1b000(0063) knlGS:00000000f50feb40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 000000000c41b50e CR3: 000000006625a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 000000000000000e 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 fb 6f 27 f8 call 0xf8277015 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 dc 6f 27 f8 call 0xf8277015 39: 4d 8b 24 24 mov (%r12),%r12 3d: e8 .byte 0xe8 3e: 13 .byte 0x13 3f: 0c .byte 0xc