syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=52e/1/0x4000000000000004 softirq=7295/7617 fqs=5195 
	(t=10500 jiffies g=5225 q=1462)
NMI backtrace for cpu 0
CPU: 0 PID: 7888 Comm: syz-executor.0 Not tainted 5.4.0-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
 rcu_pending kernel/rcu/tree.c:2827 [inline]
 rcu_sched_clock_irq.cold+0x509/0xc02 kernel/rcu/tree.c:2271
 update_process_times+0x2d/0x70 kernel/time/timer.c:1726
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167
 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1310
 __run_hrtimer kernel/time/hrtimer.c:1514 [inline]
 __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1576
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1638
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
RIP: 0010:ipv6_get_lladdr+0x0/0x490 net/ipv6/addrconf.c:1859
Code: e8 75 7c 3f fb eb a4 48 8b 3c 24 be 10 00 00 00 e8 45 7d 3f fb e9 79 ff ff ff e8 3b 7c 3f fb e9 15 fe ff ff 66 0f 1f 44 00 00 <55> 48 89 e5 41 57 41 89 d7 41 56 41 55 41 54 41 52 53 48 89 fb 48
RSP: 0018:ffff88802d609c38 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000102 RBX: ffff888079670ae8 RCX: 0000000000000000
RDX: 0000000000000040 RSI: ffff88802d609c90 RDI: ffff888068704000
RBP: ffff88802d609d00 R08: ffff88802d609c90 R09: ffff8880108148d0
R10: fffffbfff13d4e58 R11: ffffffff89ea72c7 R12: 1ffff11005ac138e
R13: ffff888079670968 R14: ffff888079670b34 R15: ffff888079670800
 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers kernel/time/timer.c:1773 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x19b/0x1e0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x4f/0x80 kernel/locking/spinlock.c:199
Code: c0 68 34 13 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 33 48 83 3d 12 6a 96 01 00 74 20 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 e7 ab d3 f9 65 8b 05 18 54 85 78 85 c0 74 06 41
RSP: 0018:ffff88801081fa80 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff122668d RBX: ffff888010814040 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880108148d4
RBP: ffff88801081fa88 R08: ffff888010814040 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88802d637380
R13: ffff888076b98ec0 R14: ffff88802ca8e980 R15: 0000000000000002
 finish_lock_switch kernel/sched/core.c:3124 [inline]
 finish_task_switch+0x147/0x750 kernel/sched/core.c:3224
 context_switch kernel/sched/core.c:3388 [inline]
 __schedule+0x8e9/0x1f30 kernel/sched/core.c:4081
 preempt_schedule_irq+0xb5/0x160 kernel/sched/core.c:4338
 retint_kernel+0x1b/0x2b
RIP: 0010:uprobe_deny_signal+0x0/0x290 kernel/events/uprobes.c:1968
Code: b6 5c 21 00 e9 a0 fe ff ff 48 8b 7d b0 e8 08 5c 21 00 e9 17 fe ff ff e8 fe 5b 21 00 e9 36 fe ff ff e9 08 2f 00 00 0f 1f 40 00 <55> 48 89 e5 41 55 41 54 53 e8 42 2e e4 ff 48 b8 00 00 00 00 00 fc
RSP: 0018:ffff88801081fca8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000040000 RBX: ffff888010814040 RCX: ffffc90006843000
RDX: 0000000000040000 RSI: ffffffff8149e777 RDI: ffff8880108147b0
RBP: ffff88801081fd68 R08: ffff888010814040 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff88801081ff58 R15: ffff88801081ff58
 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815
 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a759
Code: bd b1 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 8b b1 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007efd11059c88 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: 0000000000000003 RBX: 000000000071bf00 RCX: 000000000045a759
RDX: ffefffffffffffff RSI: 0000000000000000 RDI: 000000002001d000
RBP: 0000000000000005 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 00007efd1105a6d4
R13: 00000000004aec17 R14: 00000000006f1cb0 R15: 00000000ffffffff