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: 36 Comm: kworker/u8:2 Not tainted 6.17.0-rc2-next-20250818-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: krdsd rds_connect_worker
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 ab 91 18 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 8c 91 18 f8 4d 8b 24 24 e8 f3 9f
RSP: 0018:ffffc90000ac6eb0 EFLAGS: 00010202
RAX: 0000000000000083 RBX: ffff88805e140620 RCX: 0000000000000000
RDX: ffff8881432e9e00 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88805e140637 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000000 R12: 0000000000000418
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff1100bc280c6
FS:  0000000000000000(0000) GS:ffff888125b0b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffd CR3: 000000000e136000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 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_connect include/net/route.h:355 [inline]
 tcp_v4_connect+0x846/0x1a00 net/ipv4/tcp_ipv4.c:254
 __inet_stream_connect+0x2ab/0xe80 net/ipv4/af_inet.c:677
 inet_stream_connect+0x66/0xa0 net/ipv4/af_inet.c:748
 kernel_connect+0x113/0x180 net/socket.c:3656
 rds_tcp_conn_path_connect+0x512/0x680 net/rds/tcp_connect.c:176
 rds_connect_worker+0x1d8/0x290 net/rds/threads.c:176
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
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 ab 91 18 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 8c 91 18 f8 4d 8b 24 24 e8 f3 9f
RSP: 0018:ffffc90000ac6eb0 EFLAGS: 00010202
RAX: 0000000000000083 RBX: ffff88805e140620 RCX: 0000000000000000
RDX: ffff8881432e9e00 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88805e140637 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000000 R12: 0000000000000418
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff1100bc280c6
FS:  0000000000000000(0000) GS:ffff888125a0b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffd CR3: 0000000075412000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 3a810b1eb6134bdc 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 ab 91 18 f8       	call   0xf81891c5
  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 8c 91 18 f8       	call   0xf81891c5
  39:	4d 8b 24 24          	mov    (%r12),%r12
  3d:	e8                   	.byte 0xe8
  3e:	f3 9f                	repz lahf