Illegal XDP return value 16128, expect packet loss! ------------[ cut here ]------------ WARNING: CPU: 0 PID: 10086 at mm/maccess.c:226 copy_from_user_nofault+0x160/0x1c0 mm/maccess.c:226 Modules linked in: CPU: 0 PID: 10086 Comm: syz.4.1251 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:copy_from_user_nofault+0x160/0x1c0 mm/maccess.c:226 Code: 24 45 31 f6 31 ff 89 de e8 4d 97 d8 ff 85 db 48 c7 c0 f2 ff ff ff 49 0f 44 c6 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 d0 93 d8 ff <0f> 0b e9 1c ff ff ff 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c ea fe RSP: 0018:ffffc90000006ce8 EFLAGS: 00010246 RAX: ffffffff81a068e0 RBX: 0000000000000000 RCX: ffff88801dc38000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffc90000007117 R09: ffffc900000070e4 R10: dffffc0000000000 R11: fffff52000000e23 R12: ffff88801dc39788 R13: ffffc900010b8030 R14: ffffc90000006d48 R15: 0000000000000000 FS: 00007f36cf18f6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2d763fff CR3: 00000000648ba000 CR4: 00000000003506f0 DR0: 0000000000000004 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline] ____bpf_probe_read_user kernel/trace/bpf_trace.c:166 [inline] bpf_probe_read_user+0x26/0x70 kernel/trace/bpf_trace.c:163 bpf_prog_f2594087b0f175cc+0x32/0x834 bpf_dispatcher_nop_func include/linux/bpf.h:889 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] bpf_prog_run_pin_on_cpu include/linux/filter.h:652 [inline] bpf_flow_dissect+0x12b/0x3e0 net/core/flow_dissector.c:896 __skb_flow_dissect+0x7cc/0x6180 net/core/flow_dissector.c:1029 skb_flow_dissect_flow_keys include/linux/skbuff.h:1390 [inline] ___skb_get_hash+0x55/0x680 net/core/flow_dissector.c:1638 __skb_get_hash+0xd2/0x270 net/core/flow_dissector.c:1703 skb_get_hash include/linux/skbuff.h:1432 [inline] skb_tx_hash net/core/dev.c:3256 [inline] netdev_pick_tx+0x335/0xad0 net/core/dev.c:4153 netdev_core_pick_tx+0x141/0x300 net/core/dev.c:4186 __dev_queue_xmit+0x797/0x2e50 net/core/dev.c:4261 neigh_hh_output include/net/neighbour.h:493 [inline] neigh_output include/net/neighbour.h:507 [inline] ip6_finish_output2+0x1052/0x1530 net/ipv6/ip6_output.c:130 dst_output include/net/dst.h:452 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xb7a/0x1410 net/ipv6/ndisc.c:513 addrconf_rs_timer+0x367/0x640 net/ipv6/addrconf.c:3966 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648 expire_timers kernel/time/timer.c:1699 [inline] __run_timers+0x56c/0x810 kernel/time/timer.c:1970 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983 handle_softirqs+0x336/0x830 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194 Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 1f c1 88 f7 65 8b 05 90 e8 38 76 85 c0 74 3c 48 c7 04 24 0e 36 RSP: 0018:ffffc90002f4fa40 EFLAGS: 00000206 RAX: dffffc0000000004 RBX: 0000000000000a06 RCX: 92c345e49ab89500 RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: 0000000000000001 RBP: ffffc90002f4fad0 R08: ffff8880b903b30b R09: 1ffff11017207661 R10: dffffc0000000000 R11: ffffed1017207662 R12: dffffc0000000000 R13: ffff8880b903b098 R14: ffff88802921a7d0 R15: 1ffff920005e9f48 try_to_wake_up+0x668/0x1020 kernel/sched/core.c:4167 wake_up_process kernel/sched/core.c:4234 [inline] wake_up_q+0x78/0xc0 kernel/sched/core.c:953 futex_wake+0x4a9/0x540 kernel/futex/core.c:1702 do_futex+0xd83/0x12b0 kernel/futex/core.c:3988 __do_sys_futex kernel/futex/core.c:4060 [inline] __se_sys_futex+0x389/0x420 kernel/futex/core.c:4041 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f36d0f370d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f36cf18f0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f36d11befa8 RCX: 00007f36d0f370d9 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f36d11befac RBP: 00007f36d11befa0 R08: 00181da95fd5821a R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f36d11bf038 R14: 00007ffda812dfc0 R15: 00007ffda812e0a8 ---------------- Code disassembly (best guess): 0: c7 44 24 20 00 00 00 movl $0x0,0x20(%rsp) 7: 00 8: 9c pushf 9: 8f 44 24 20 pop 0x20(%rsp) d: f7 44 24 20 00 02 00 testl $0x200,0x20(%rsp) 14: 00 15: 41 c6 04 07 f8 movb $0xf8,(%r15,%rax,1) 1a: 75 4b jne 0x67 1c: f7 c3 00 02 00 00 test $0x200,%ebx 22: 74 01 je 0x25 24: fb sti 25: bf 01 00 00 00 mov $0x1,%edi * 2a: e8 1f c1 88 f7 call 0xf788c14e <-- trapping instruction 2f: 65 8b 05 90 e8 38 76 mov %gs:0x7638e890(%rip),%eax # 0x7638e8c6 36: 85 c0 test %eax,%eax 38: 74 3c je 0x76 3a: 48 rex.W 3b: c7 .byte 0xc7 3c: 04 24 add $0x24,%al 3e: 0e (bad) 3f: 36 ss