syzbot

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: 26289 Comm: syz.5.6590 Tainted: G        W         syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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 de 6e 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 b0 6e bf fd 48 8b 1b 48 85 db 74 68
RSP: 0018:ffffc90000170408 EFLAGS: 00010202
RAX: 000000000000005b RBX: 00000000000002d8 RCX: dffffc0000000000
RDX: ffff888131a93b40 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000170478 R08: ffff888131a93b40 R09: 0000000000000003
R10: 0000000000000008 R11: 0000000080000301 R12: ffff88812f215600
R13: 0000000000000000 R14: 0000000000000000 R15: ffff888111de2790
FS:  00007f3a4706d6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4e2bd8df98 CR3: 000000011ed0e000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 fib_table_lookup+0xe4c/0x1730 net/ipv4/fib_trie.c:1542
 fib4_rule_action+0x115/0x1a0 net/ipv4/fib_rules.c:135
 fib_rules_lookup+0x489/0x8d0 net/core/fib_rules.c:318
 __fib_lookup+0xe4/0x150 net/ipv4/fib_rules.c:92
 fib_lookup include/net/ip_fib.h:371 [inline]
 ip_route_output_key_hash_rcu+0x345/0x20e0 net/ipv4/route.c:2674
 ip_route_output_key_hash net/ipv4/route.c:2564 [inline]
 __ip_route_output_key include/net/route.h:126 [inline]
 ip_route_output_flow+0x123/0x2d0 net/ipv4/route.c:2796
 ip_route_output_key include/net/route.h:142 [inline]
 tipc_udp_xmit+0x1aa/0x8e0 net/tipc/udp_media.c:183
 tipc_udp_send_msg+0x20c/0x2e0 net/tipc/udp_media.c:265
 tipc_bearer_xmit_skb+0x27d/0x360 net/tipc/bearer.c:548
 tipc_disc_timeout+0x6a2/0x830 net/tipc/discover.c:337
 call_timer_fn+0x38/0x290 kernel/time/timer.c:1450
 expire_timers kernel/time/timer.c:1495 [inline]
 __run_timers+0x639/0x9a0 kernel/time/timer.c:1789
 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1802
 __do_softirq+0x255/0x563 kernel/softirq.c:309
 asm_call_irq_on_stack+0xf/0x20
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline]
 do_softirq_own_stack+0x60/0x80 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:405 [inline]
 __irq_exit_rcu+0x128/0x150 kernel/softirq.c:435
 irq_exit_rcu+0x9/0x10 kernel/softirq.c:447
 sysvec_apic_timer_interrupt+0xbf/0xe0 arch/x86/kernel/apic/apic.c:1106
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635
RIP: 0010:selinux_socket_unix_may_send+0x0/0x280 security/selinux/hooks.c:5027
Code: f1 80 e1 07 80 c1 03 38 c1 0f 8c 6e fe ff ff 4c 89 f7 e8 b3 37 86 ff 48 ba 00 00 00 00 00 fc ff df e9 57 fe ff ff 0f 1f 40 00 <55> 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec 00 01
RSP: 0018:ffffc9000195f740 EFLAGS: 00000246
RAX: 1ffffffff0b38dc0 RBX: ffff888132b50b40 RCX: 0000000000080000
RDX: ffffc90009a0e000 RSI: ffff888132b50b40 RDI: ffff888132b53480
RBP: ffffc9000195f770 R08: dffffc0000000000 R09: ffffed1025f8edad
R10: ffffed1025f8edad R11: 1ffff11025f8edac R12: ffffffff859c6e00
R13: dffffc0000000000 R14: ffff888132b53480 R15: ffffffff859c6de8
 unix_dgram_sendmsg+0xcad/0x17d0 net/unix/af_unix.c:1805
 sock_sendmsg_nosec net/socket.c:652 [inline]
 __sock_sendmsg net/socket.c:664 [inline]
 ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2376
 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2430
 __sys_sendmmsg+0x273/0x450 net/socket.c:2516
 __do_sys_sendmmsg net/socket.c:2545 [inline]
 __se_sys_sendmmsg net/socket.c:2542 [inline]
 __x64_sys_sendmmsg+0xa0/0xb0 net/socket.c:2542
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f3a48604ec9
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:00007f3a4706d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f3a4885bfa0 RCX: 00007f3a48604ec9
RDX: 0000000000000651 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007f3a48687f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3a4885c038 R14: 00007f3a4885bfa0 R15: 00007ffdae22fde8
Modules linked in:
---[ end trace 04d5354002a5ec70 ]---
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 de 6e 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 b0 6e bf fd 48 8b 1b 48 85 db 74 68
RSP: 0018:ffffc90000170408 EFLAGS: 00010202
RAX: 000000000000005b RBX: 00000000000002d8 RCX: dffffc0000000000
RDX: ffff888131a93b40 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000170478 R08: ffff888131a93b40 R09: 0000000000000003
R10: 0000000000000008 R11: 0000000080000301 R12: ffff88812f215600
R13: 0000000000000000 R14: 0000000000000000 R15: ffff888111de2790
FS:  00007f3a4706d6c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4e2bd8df98 CR3: 000000011ed0e000 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 de 6e bf fd       	call   0xfdbf6ee8
   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 b0 6e bf fd       	call   0xfdbf6ee8
  38:	48 8b 1b             	mov    (%rbx),%rbx
  3b:	48 85 db             	test   %rbx,%rbx
  3e:	74 68                	je     0xa8