rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (10499 ticks this GP) idle=a92/1/0x4000000000000000 softirq=13315/13315 fqs=5221 
	(t=10500 jiffies g=17089 q=13140)
NMI backtrace for cpu 1
CPU: 1 PID: 10931 Comm: syz-executor.3 Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x194/0x1cf kernel/rcu/tree_stall.h:320
 print_cpu_stall kernel/rcu/tree_stall.h:553 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:627 [inline]
 rcu_pending kernel/rcu/tree.c:3489 [inline]
 rcu_sched_clock_irq.cold+0x5b3/0xccc kernel/rcu/tree.c:2504
 update_process_times+0x25/0x60 kernel/time/timer.c:1737
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176
 tick_sched_timer+0x108/0x290 kernel/time/tick-sched.c:1320
 __run_hrtimer kernel/time/hrtimer.c:1520 [inline]
 __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1584
 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1646
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0x142/0x5e0 arch/x86/kernel/apic/apic.c:1097
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711
 </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]
 sysvec_apic_timer_interrupt+0xe0/0x120 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:585
RIP: 0010:__sanitizer_cov_trace_pc+0x55/0x60 kernel/kcov.c:207
Code: 82 e0 13 00 00 83 f8 02 75 20 48 8b 8a e8 13 00 00 8b 92 e4 13 00 00 48 8b 01 48 83 c0 01 48 39 c2 76 07 48 89 34 c1 48 89 01 <c3> 66 2e 0f 1f 84 00 00 00 00 00 41 55 41 54 49 89 fc 55 48 bd eb
RSP: 0018:ffffc90004ac70d0 EFLAGS: 00000246
RAX: 0000000000040000 RBX: ffffc90004ac7420 RCX: ffffc9000f739000
RDX: 0000000000040000 RSI: ffffffff818d3eff RDI: ffff8880a217b2e0
RBP: 0000000000000010 R08: 0000000000000000 R09: ffff8880a217b0bf
R10: 0000000000000000 R11: 0000000000000001 R12: ffffc90004ac7210
R13: dffffc0000000000 R14: 1ffff92000958e89 R15: ffff8880a217b000
 __output_copy kernel/events/internal.h:178 [inline]
 perf_output_read_group kernel/events/core.c:6699 [inline]
 perf_output_read+0xcff/0x1260 kernel/events/core.c:6732
 perf_output_sample+0x102c/0x1c60 kernel/events/core.c:6779
 __perf_event_output kernel/events/core.c:7160 [inline]
 perf_event_output_forward+0x12f/0x270 kernel/events/core.c:7174
 __perf_event_overflow+0x13c/0x370 kernel/events/core.c:8746
 perf_swevent_overflow kernel/events/core.c:8822 [inline]
 perf_swevent_event+0x347/0x550 kernel/events/core.c:8850
 do_perf_sw_event kernel/events/core.c:8963 [inline]
 ___perf_sw_event+0x304/0x550 kernel/events/core.c:8994
 __perf_sw_event+0x58/0x120 kernel/events/core.c:9006
 perf_sw_event include/linux/perf_event.h:1158 [inline]
 do_user_addr_fault+0x82a/0xd00 arch/x86/mm/fault.c:1332
 handle_page_fault arch/x86/mm/fault.c:1365 [inline]
 exc_page_fault+0xab/0x170 arch/x86/mm/fault.c:1418
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:542
RIP: 0010:copy_user_enhanced_fast_string+0xe/0x30 arch/x86/lib/copy_user_64.S:205
Code: 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 1f 00 c3 0f 1f 80 00 00 00 00 0f 1f 00 83 fa 40 0f 82 70 ff ff ff 89 d1 <f3> a4 31 c0 0f 1f 00 c3 66 2e 0f 1f 84 00 00 00 00 00 89 d1 f3 a4
RSP: 0018:ffffc90004ac79b8 EFLAGS: 00010206
RAX: 0000000000000001 RBX: 0000000000008000 RCX: 0000000000006fcb
RDX: 0000000000008000 RSI: 0000000020fe6000 RDI: ffff888053171035
RBP: ffff888053170000 R08: 0000000000000001 R09: ffff888053177fff
R10: ffffed100a62efff R11: 0000000000000000 R12: 0000000020fe4fcb
R13: 0000000020fecfcb R14: 00007ffffffff000 R15: 0000000000000000
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_from_user arch/x86/include/asm/uaccess_64.h:68 [inline]
 copyin+0x107/0x140 lib/iov_iter.c:152
 _copy_from_iter_full+0x1ff/0x890 lib/iov_iter.c:790
 copy_from_iter_full include/linux/uio.h:156 [inline]
 skb_do_copy_data_nocache+0x145/0x2c0 include/net/sock.h:2038
 skb_copy_to_page_nocache include/net/sock.h:2064 [inline]
 tcp_sendmsg_locked+0x112c/0x2d00 net/ipv4/tcp.c:1343
 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1441
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:814
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 __sys_sendto+0x21c/0x320 net/socket.c:1995
 __do_sys_sendto net/socket.c:2007 [inline]
 __se_sys_sendto net/socket.c:2003 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2003
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c369
Code: 8d b6 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 5b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007febfd56ac78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000000000002ba00 RCX: 000000000045c369
RDX: ffffffffffffffef RSI: 0000000020d7cfcb RDI: 0000000000000008
RBP: 000000000078bf58 R08: 0000000000000000 R09: 0000000000000053
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007fff8169d74f R14: 00007febfd56b9c0 R15: 000000000078bf0c