syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 GPs behind) idle=dca/1/0x4000000000000002 softirq=12967/12968 fqs=5247 
	(detected by 1, t=10502 jiffies, g=15325, q=1610)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 9057 Comm: syz-executor.1 Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x26/0x60 kernel/kcov.c:197
Code: 31 c0 c3 90 65 48 8b 14 25 c0 fe 01 00 65 8b 05 60 bf 8d 7e a9 00 01 ff 00 48 8b 34 24 74 0f f6 c4 01 74 35 8b 82 24 14 00 00 <85> c0 74 2b 8b 82 00 14 00 00 83 f8 02 75 20 48 8b 8a 08 14 00 00
RSP: 0018:ffffc90000007910 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 0000000000000086 RCX: 0000000000000000
RDX: ffff8880a92063c0 RSI: ffffffff8179ffed RDI: ffffffff89843900
RBP: 0000000000000000 R08: 0000000000000001 R09: ffff8880a9206ca0
R10: ffffc90000007818 R11: 0000000000000001 R12: dffffc0000000000
R13: ffffffff88000d82 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f27918fe700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000009e75c000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 trace_hardirqs_off+0xd/0x210 kernel/trace/trace_preemptirq.c:76
 rcu_irq_exit_irqson+0x71/0x140 kernel/rcu/tree.c:827
 trace_irq_enable_rcuidle include/trace/events/preemptirq.h:40 [inline]
 trace_irq_enable_rcuidle include/trace/events/preemptirq.h:40 [inline]
 trace_hardirqs_on+0x1aa/0x220 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x12/0x20 arch/x86/include/asm/idtentry.h:611
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:770 [inline]
RIP: 0010:rcu_read_unlock_special kernel/rcu/tree_plugin.h:630 [inline]
RIP: 0010:__rcu_read_unlock+0x488/0x560 kernel/rcu/tree_plugin.h:395
Code: 48 c7 c0 c8 3b b6 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 53 48 83 3d 47 75 54 08 00 74 13 4c 89 e7 57 9d <0f> 1f 44 00 00 e9 ed fb ff ff 0f 0b 0f 0b 0f 0b 0f 0b 4c 89 ef e8
RSP: 0018:ffffc90000007a30 EFLAGS: 00000286
RAX: 1ffffffff136c779 RBX: ffffffff89bd9901 RCX: 0000000000000002
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000286
RBP: 0000000000000001 R08: 0000000000000001 R09: ffffffff8c5f3a97
R10: fffffbfff18be752 R11: 0000000000000001 R12: 0000000000000286
R13: 0000000000000200 R14: ffff8880ae636c00 R15: 0000000000000000
 rcu_read_unlock include/linux/rcupdate.h:687 [inline]
 ndisc_send_skb+0xd41/0x1720 net/ipv6/ndisc.c:514
 ndisc_send_rs+0x12e/0x700 net/ipv6/ndisc.c:700
 addrconf_rs_timer+0x2ec/0x7c0 net/ipv6/addrconf.c:3873
 call_timer_fn+0x1ac/0x760 kernel/time/timer.c:1413
 expire_timers kernel/time/timer.c:1458 [inline]
 __run_timers.part.0+0x67c/0xaa0 kernel/time/timer.c:1755
 __run_timers kernel/time/timer.c:1736 [inline]
 run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768
 __do_softirq+0x2de/0xa24 kernel/softirq.c:298
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:393 [inline]
 __irq_exit_rcu kernel/softirq.c:423 [inline]
 irq_exit_rcu+0x1f3/0x230 kernel/softirq.c:435
 sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x4b/0x80 kernel/locking/spinlock.c:199
Code: c0 d8 3b b6 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 31 48 83 3d 46 f6 bf 01 00 74 25 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 db 6d 59 f9 65 8b 05 d4 b8 0b 78 85 c0 74 02 5d
RSP: 0018:ffffc90004207bc8 EFLAGS: 00000286
RAX: 1ffffffff136c77b RBX: ffff8880a92063c0 RCX: 0000000000000006
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff87f6456f
RBP: ffff8880ae635e00 R08: 0000000000000001 R09: ffffffff8c5f3ae7
R10: fffffbfff18be75c R11: 0000000000000001 R12: ffff8880ae635e00
R13: ffff88807973a040 R14: 0000000000000000 R15: 0000000000000001
 finish_lock_switch kernel/sched/core.c:3517 [inline]
 finish_task_switch+0x147/0x750 kernel/sched/core.c:3617
 context_switch kernel/sched/core.c:3781 [inline]
 __schedule+0x8ed/0x21e0 kernel/sched/core.c:4527
 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:4683
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:40
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
 _raw_spin_unlock_irqrestore+0xb2/0xe0 kernel/locking/spinlock.c:191
 perf_unpin_context kernel/events/core.c:1520 [inline]
 __do_sys_perf_event_open+0x1c7e/0x2cb0 kernel/events/core.c:11993
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5b9
Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f27918fdc78 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 0000000000024780 RCX: 000000000045d5b9
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000000020000180
RBP: 000000000118cf90 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffe0321093f R14: 00007f27918fe9c0 R15: 000000000118cf4c