rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-....: (1 GPs behind) idle=b8d/1/0x4000000000000002 softirq=39738/39739 fqs=2100 (detected by 1, t=10503 jiffies, g=55185, q=1432) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 15294 Comm: syz.5.2673 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x58/0x60 kernel/kcov.c:216 Code: 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14 16 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 3a 0f 1f 80 00 00 00 00 48 8b 04 24 65 48 8b 0d 64 26 89 7e 65 8b RSP: 0018:ffffc90000006eb0 EFLAGS: 00000046 RAX: ffffffff819c3995 RBX: ffff8880683e85f8 RCX: ffff88802b491dc0 RDX: 0000000000000100 RSI: ffffc90000007200 RDI: ffffc90000007040 RBP: ffffc90000006ff0 R08: ffffc90000007077 R09: ffffc90000007040 R10: dffffc0000000000 R11: fffff52000000e0f R12: 1ffff92000000de8 R13: ffffc90000007040 R14: 0000000000000008 R15: dffffc0000000000 FS: 00007f13ade7a6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8f39fa24e8 CR3: 000000001fe0c000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312 rcu_read_lock include/linux/rcupdate.h:740 [inline] __perf_output_begin kernel/events/ring_buffer.c:163 [inline] perf_output_begin_forward+0xa5/0xa40 kernel/events/ring_buffer.c:271 __perf_event_output kernel/events/core.c:7804 [inline] perf_event_output_forward+0x19b/0x2e0 kernel/events/core.c:7822 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 f2 cc 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0018:ffffc90000007620 EFLAGS: 00000206 RAX: 1d3ad970e4d95a00 RBX: 1ffff92000000ec8 RCX: 1d3ad970e4d95a00 RDX: dffffc0000000000 RSI: ffffffff8a2b3180 RDI: ffffffff8a7a09c0 RBP: ffffc90000007700 R08: ffffffff901d81ef R09: 1ffffffff203b03d R10: dffffc0000000000 R11: fffffbfff203b03e R12: ffffffff8c323800 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] ndisc_send_skb+0xde0/0x1500 net/ipv6/ndisc.c:521 ndisc_send_ns+0x648/0x850 net/ipv6/ndisc.c:655 ndisc_solicit+0x300/0x4f0 net/ipv6/ndisc.c:747 neigh_probe net/core/neighbour.c:1017 [inline] neigh_timer_handler+0xaa9/0xfe0 net/core/neighbour.c:1099 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648 expire_timers kernel/time/timer.c:1699 [inline] __run_timers+0x53e/0x800 kernel/time/timer.c:1970 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983 handle_softirqs+0x339/0x830 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:check_kcov_mode kernel/kcov.c:174 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x2c/0x60 kernel/kcov.c:206 Code: 04 24 65 48 8b 0d c4 26 89 7e 65 8b 15 c5 26 89 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00 00 74 2c <8b> 91 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 RSP: 0018:ffffc90003f97c00 EFLAGS: 00000246 RAX: ffffffff81810dec RBX: ffffffff8c5656e0 RCX: ffff88802b491dc0 RDX: 0000000000000000 RSI: 0000000000000364 RDI: 0000000000000000 RBP: 0000000000000002 R08: ffffc90003f979e7 R09: 1ffff920007f2f3c R10: dffffc0000000000 R11: fffff520007f2f3d R12: 0000000000000364 R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000000 perf_trace_init+0x1ac/0x2d0 kernel/trace/trace_event_perf.c:222 perf_tp_event_init+0x89/0x110 kernel/events/core.c:10102 perf_try_init_event+0x12b/0x3d0 kernel/events/core.c:11601 perf_init_event kernel/events/core.c:11665 [inline] perf_event_alloc+0xfcf/0x2240 kernel/events/core.c:11957 __do_sys_perf_event_open kernel/events/core.c:12495 [inline] __se_sys_perf_event_open+0x5de/0x1bb0 kernel/events/core.c:12387 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: 0033:0x7f13afc20e59 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:00007f13ade7a028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007f13afe99fa0 RCX: 00007f13afc20e59 RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000200000000380 RBP: 00007f13afcb6d6f R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f13afe9a038 R14: 00007f13afe99fa0 R15: 00007ffc4955cfc8