rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (10499 ticks this GP) idle=b62/1/0x4000000000000002 softirq=60835/60835 fqs=5229 
	(t=10500 jiffies g=84073 q=742)
NMI backtrace for cpu 1
CPU: 1 PID: 22348 Comm: syz-executor.4 Not tainted 5.6.0-rc5-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+0x188/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x169/0x1b3 kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:475 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:549 [inline]
 rcu_pending kernel/rcu/tree.c:3030 [inline]
 rcu_sched_clock_irq.cold+0x518/0xc55 kernel/rcu/tree.c:2276
 update_process_times+0x25/0x60 kernel/time/timer.c:1726
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:171
 tick_sched_timer+0x4e/0x140 kernel/time/tick-sched.c:1314
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x32c/0xdd0 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x312/0x770 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1119 [inline]
 smp_apic_timer_interrupt+0x15b/0x600 arch/x86/kernel/apic/apic.c:1144
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:__output_copy kernel/events/internal.h:178 [inline]
RIP: 0010:perf_output_read_group kernel/events/core.c:6520 [inline]
RIP: 0010:perf_output_read+0xdeb/0x11f0 kernel/events/core.c:6553
Code: 20 01 00 00 48 89 fe 48 c1 ee 03 42 80 3c 26 00 0f 85 a0 01 00 00 48 8b 84 c2 20 01 00 00 49 c7 45 18 00 10 00 00 49 89 45 28 <e8> 00 b5 e7 ff 48 89 de 48 89 ef e8 05 b6 e7 ff 48 39 dd 0f 82 d0
RSP: 0018:ffffc90016967140 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000002 RBX: 0000000000000010 RCX: ffffffff818a5dc7
RDX: 0000000000000388 RSI: 0000000000000388 RDI: 0000000000000007
RBP: 0000000000000398 R08: ffff88805912e300 R09: ffffed101205418f
R10: ffffed101205418e R11: ffff8880902a0c77 R12: dffffc0000000000
R13: ffffc90016967498 R14: ffffc90016967298 R15: ffff88806c55b000
 perf_output_sample+0x149b/0x1b30 kernel/events/core.c:6595
 __perf_event_output kernel/events/core.c:6955 [inline]
 perf_event_output_forward+0x12f/0x270 kernel/events/core.c:6969
 __perf_event_overflow+0x13c/0x370 kernel/events/core.c:8436
 perf_swevent_overflow+0xac/0x150 kernel/events/core.c:8512
 perf_swevent_event+0x1e9/0x2e0 kernel/events/core.c:8545
 do_perf_sw_event kernel/events/core.c:8653 [inline]
 ___perf_sw_event+0x31c/0x570 kernel/events/core.c:8684
 __perf_sw_event+0x4b/0xa0 kernel/events/core.c:8696
 perf_sw_event include/linux/perf_event.h:1138 [inline]
 do_user_addr_fault arch/x86/mm/fault.c:1483 [inline]
 do_page_fault+0xaaa/0x12da arch/x86/mm/fault.c:1517
 page_fault+0x39/0x40 arch/x86/entry/entry_64.S:1203
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:ffffc90016967a58 EFLAGS: 00010206
RAX: 0000000000000001 RBX: 0000000000008000 RCX: 0000000000000fcb
RDX: 0000000000008000 RSI: 0000000020fec000 RDI: ffff888060767035
RBP: 0000000020fe4fcb R08: ffffed100c0ed000 R09: 0000000000000000
R10: ffffed100c0ecfff R11: ffff888060767fff R12: ffff888060760000
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:71 [inline]
 copyin+0x11c/0x140 lib/iov_iter.c:151
 _copy_from_iter_full+0x20a/0x870 lib/iov_iter.c:789
 copy_from_iter_full include/linux/uio.h:156 [inline]
 skb_do_copy_data_nocache include/net/sock.h:2002 [inline]
 skb_copy_to_page_nocache include/net/sock.h:2028 [inline]
 tcp_sendmsg_locked+0x131a/0x3210 net/ipv4/tcp.c:1335
 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1433
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 __sys_sendto+0x21a/0x330 net/socket.c:1998
 __do_sys_sendto net/socket.c:2010 [inline]
 __se_sys_sendto net/socket.c:2006 [inline]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2006
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c4a9
Code: ad 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f21e3597c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f21e35986d4 RCX: 000000000045c4a9
RDX: ffffffffffffffef RSI: 0000000020d7cfcb RDI: 0000000000000006
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000a03 R14: 00000000004cc7f0 R15: 000000000076bf2c