rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (10498 ticks this GP) idle=09e/1/0x4000000000000000 softirq=12956/12956 fqs=5249 
	(t=10501 jiffies g=12865 q=1253)
NMI backtrace for cpu 1
CPU: 1 PID: 10056 Comm: syz-executor.4 Not tainted 5.10.0-next-20201223-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:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:165 [inline]
 rcu_dump_cpu_stacks+0x1e3/0x21e kernel/rcu/tree_stall.h:337
 print_cpu_stall kernel/rcu/tree_stall.h:569 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:643 [inline]
 rcu_pending kernel/rcu/tree.c:3751 [inline]
 rcu_sched_clock_irq.cold+0x472/0xec3 kernel/rcu/tree.c:2580
 update_process_times+0x16d/0x200 kernel/time/timer.c:1782
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226
 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1376
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x1ce/0xea0 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0x334/0x940 kernel/time/hrtimer.c:1645
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
 __sysvec_apic_timer_interrupt+0x146/0x540 arch/x86/kernel/apic/apic.c:1102
 asm_call_irq_on_stack+0xf/0x20
 </IRQ>
 __run_sysvec_on_irqstack arch/x86/include/asm/irq_stack.h:37 [inline]
 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:89 [inline]
 sysvec_apic_timer_interrupt+0xbd/0x100 arch/x86/kernel/apic/apic.c:1096
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:628
RIP: 0010:check_memory_region+0xe/0x180 mm/kasan/generic.c:185
Code: f5 00 00 00 e9 b3 9c 25 02 0f 1f 00 48 89 f2 be f8 00 00 00 e9 a3 9c 25 02 0f 1f 00 48 85 f6 0f 84 70 01 00 00 49 89 f9 41 54 <44> 0f b6 c2 49 01 f1 55 53 0f 82 18 01 00 00 48 b8 ff ff ff ff ff
RSP: 0018:ffffc90000f4f008 EFLAGS: 00000202
RAX: ffff888023df7000 RBX: ffffc90000f4f360 RCX: ffffffff818eaaea
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff888023df70b8
RBP: 0000000000000000 R08: 0000000000000000 R09: ffff888023df70b8
R10: ffffed10047bee16 R11: 0000000000000001 R12: ffff888023df70b8
R13: dffffc0000000000 R14: ffff888023df7000 R15: 0000000000000010
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 atomic64_read include/asm-generic/atomic-instrumented.h:837 [inline]
 perf_event_count kernel/events/core.c:4276 [inline]
 perf_output_read_group kernel/events/core.c:6740 [inline]
 perf_output_read+0xc5a/0x1310 kernel/events/core.c:6777
 perf_output_sample+0xd12/0x1be0 kernel/events/core.c:6824
 __perf_event_output kernel/events/core.c:7309 [inline]
 perf_event_output_forward+0x132/0x270 kernel/events/core.c:7323
 __perf_event_overflow+0x13c/0x370 kernel/events/core.c:8979
 perf_swevent_overflow kernel/events/core.c:9055 [inline]
 perf_swevent_event+0x347/0x550 kernel/events/core.c:9083
 do_perf_sw_event kernel/events/core.c:9196 [inline]
 ___perf_sw_event+0x31a/0x570 kernel/events/core.c:9227
 __perf_sw_event+0x54/0x130 kernel/events/core.c:9239
 perf_sw_event include/linux/perf_event.h:1167 [inline]
 mm_account_fault mm/memory.c:4583 [inline]
 handle_mm_fault+0x10d3/0x5640 mm/memory.c:4634
 do_user_addr_fault+0x570/0xc50 arch/x86/mm/fault.c:1398
 handle_page_fault arch/x86/mm/fault.c:1455 [inline]
 exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1511
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:580
RIP: 0010:copy_user_enhanced_fast_string+0xe/0x40 arch/x86/lib/copy_user_64.S:206
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 83 f8
RSP: 0018:ffffc90000f4f9c8 EFLAGS: 00010206
RAX: 0000000000000001 RBX: 0000000000008000 RCX: 0000000000006fcb
RDX: 0000000000008000 RSI: 0000000020f6e000 RDI: ffff88807c2f9035
RBP: ffff88807c2f8000 R08: 0000000000000001 R09: ffff88807c2fffff
R10: ffffed100f85ffff R11: 0000000000000000 R12: 0000000020f6cfcb
R13: 0000000020f74fcb R14: 0000000000000000 R15: ffffc90000f4fda8
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_from_user arch/x86/include/asm/uaccess_64.h:52 [inline]
 copyin.part.0+0xe4/0x110 lib/iov_iter.c:159
 copyin lib/iov_iter.c:795 [inline]
 _copy_from_iter_full+0x228/0x850 lib/iov_iter.c:795
 copy_from_iter_full include/linux/uio.h:155 [inline]
 skb_do_copy_data_nocache+0x145/0x2c0 include/net/sock.h:2054
 skb_copy_to_page_nocache include/net/sock.h:2080 [inline]
 tcp_sendmsg_locked+0x12ea/0x2d20 net/ipv4/tcp.c:1362
 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1459
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:817
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 __sys_sendto+0x21c/0x320 net/socket.c:1975
 __do_sys_sendto net/socket.c:1987 [inline]
 __se_sys_sendto net/socket.c:1983 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:1983
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e299
Code: 0d 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f5346129c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 000000000045e299
RDX: ffffffffffffffef RSI: 0000000020d7cfcb RDI: 0000000000000004
RBP: 000000000119bfd8 R08: 0000000000000000 R09: 0000000000000053
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c
R13: 00007ffcb65d605f R14: 00007f534612a9c0 R15: 000000000119bf8c