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: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 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 db 3c 1a 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 bc 3c 1a f8 4d 8b 24 24 e8 73 f7 RSP: 0018:ffffc90000126eb0 EFLAGS: 00010202 RAX: 0000000000000083 RBX: ffff88802e291720 RCX: 0000000000000000 RDX: ffff88801ce98000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88802e291737 R08: 0000000000000000 R09: ffffffff8a0ef11f R10: 0000000000000008 R11: 0000000000000000 R12: 0000000000000418 R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff11005c522e6 FS: 0000000000000000(0000) GS:ffff888125c13000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2b1e7056c0 CR3: 000000000df36000 CR4: 00000000003526f0 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:139 fib_rules_lookup+0x8a6/0xe90 net/core/fib_rules.c:339 __fib_lookup+0xf9/0x200 net/ipv4/fib_rules.c:96 ip_route_output_key_hash_rcu+0x31b/0x23e0 net/ipv4/route.c:2809 ip_route_output_key_hash+0x174/0x280 net/ipv4/route.c:2700 __ip_route_output_key include/net/route.h:169 [inline] ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2927 ip_route_connect include/net/route.h:355 [inline] tcp_v4_connect+0x846/0x1a00 net/ipv4/tcp_ipv4.c:254 __inet_stream_connect+0x2ae/0xe80 net/ipv4/af_inet.c:677 inet_stream_connect+0x66/0xa0 net/ipv4/af_inet.c:748 kernel_connect+0x116/0x180 net/socket.c:3656 rds_tcp_conn_path_connect+0x512/0x680 net/rds/tcp_connect.c:176 rds_connect_worker+0x1d5/0x290 net/rds/threads.c:176 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 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 db 3c 1a 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 bc 3c 1a f8 4d 8b 24 24 e8 73 f7 RSP: 0018:ffffc90000126eb0 EFLAGS: 00010202 RAX: 0000000000000083 RBX: ffff88802e291720 RCX: 0000000000000000 RDX: ffff88801ce98000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88802e291737 R08: 0000000000000000 R09: ffffffff8a0ef11f R10: 0000000000000008 R11: 0000000000000000 R12: 0000000000000418 R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff11005c522e6 FS: 0000000000000000(0000) GS:ffff888125c13000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f03ec53dfb8 CR3: 0000000072944000 CR4: 00000000003526f0 ---------------- 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 db 3c 1a f8 call 0xf81a3cf5 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 bc 3c 1a f8 call 0xf81a3cf5 39: 4d 8b 24 24 mov (%r12),%r12 3d: e8 .byte 0xe8 3e: 73 f7 jae 0x37