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: 23690 Comm: kworker/u8:62 Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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 6b 89 2c 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 4c 89 2c f8 4d 8b 24 24 e8 33 fc RSP: 0018:ffffc9000ad06ed0 EFLAGS: 00010202 RAX: 0000000000000083 RBX: ffff888057782320 RCX: 0000000000000000 RDX: ffff88802ffa3c00 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff888057782337 R08: 0000000000000000 R09: ffffffff89f9773f R10: 0000000000000008 R11: 0000000000000000 R12: 0000000000000418 R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff1100aef0466 FS: 0000000000000000(0000) GS:ffff888125d57000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33c1dff8 CR3: 000000005869c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 00000000000032e7 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+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_connect include/net/route.h:355 [inline] tcp_v4_connect+0x82f/0x19d0 net/ipv4/tcp_ipv4.c:252 __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:3608 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:3238 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 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 6b 89 2c 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 4c 89 2c f8 4d 8b 24 24 e8 33 fc RSP: 0018:ffffc9000ad06ed0 EFLAGS: 00010202 RAX: 0000000000000083 RBX: ffff888057782320 RCX: 0000000000000000 RDX: ffff88802ffa3c00 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff888057782337 R08: 0000000000000000 R09: ffffffff89f9773f R10: 0000000000000008 R11: 0000000000000000 R12: 0000000000000418 R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff1100aef0466 ---------------- 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 6b 89 2c f8 call 0xf82c8985 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 4c 89 2c f8 call 0xf82c8985 39: 4d 8b 24 24 mov (%r12),%r12 3d: e8 .byte 0xe8 3e: 33 fc xor %esp,%edi