syzbot

block nbd5: shutting down sockets
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (10499 ticks this GP) idle=582/1/0x4000000000000002 softirq=217383/217383 fqs=5249 
rcu: 	 (t=10501 jiffies g=294805 q=1319)
NMI backtrace for cpu 0
CPU: 0 PID: 26641 Comm: syz-executor.3 Not tainted 4.19.72 #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+0x172/0x1f0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b0/0x1f8 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+0x189/0x1d5 kernel/rcu/tree.c:1340
 print_cpu_stall kernel/rcu/tree.c:1478 [inline]
 check_cpu_stall kernel/rcu/tree.c:1550 [inline]
 __rcu_pending kernel/rcu/tree.c:3293 [inline]
 rcu_pending kernel/rcu/tree.c:3336 [inline]
 rcu_check_callbacks.cold+0x5e3/0xd90 kernel/rcu/tree.c:2682
 update_process_times+0x32/0x80 kernel/time/timer.c:1636
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:164
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1274
 __run_hrtimer kernel/time/hrtimer.c:1398 [inline]
 __hrtimer_run_queues+0x33b/0xdc0 kernel/time/hrtimer.c:1460
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1518
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline]
 smp_apic_timer_interrupt+0x111/0x550 arch/x86/kernel/apic/apic.c:1092
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
 </IRQ>
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x50 kernel/kcov.c:100
Code: 66 ea ff 48 c7 05 44 22 cd 08 00 00 00 00 e9 ca e9 ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 48 8b 75 08 <65> 48 8b 04 25 40 ee 01 00 65 8b 15 28 97 96 7e 81 e2 00 01 1f 00
RSP: 0018:ffff88806b83f0d0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: ffffed100d707e8e RBX: 0000000000000000 RCX: ffff88806b83f230
RDX: 0000000000040000 RSI: ffffffff81800ea5 RDI: ffff88808a4d51a0
RBP: ffff88806b83f0d0 R08: ffff888066f48000 R09: ffffed101149a9b8
R10: ffffed101149a9b7 R11: ffff88808a4d4dbf R12: 0000000000000010
R13: dffffc0000000000 R14: ffff88806b83f230 R15: ffff88806b83f448
 __output_copy kernel/events/internal.h:176 [inline]
 perf_output_read_group kernel/events/core.c:6178 [inline]
 perf_output_read+0xdd5/0x1390 kernel/events/core.c:6211
 perf_output_sample+0x13b6/0x1a90 kernel/events/core.c:6253
 __perf_event_output kernel/events/core.c:6575 [inline]
 perf_event_output_forward+0x150/0x290 kernel/events/core.c:6588
 __perf_event_overflow+0x141/0x370 kernel/events/core.c:7834
 perf_swevent_overflow+0xaa/0x140 kernel/events/core.c:7910
 perf_swevent_event+0x1f7/0x2f0 kernel/events/core.c:7943
 do_perf_sw_event kernel/events/core.c:8051 [inline]
 ___perf_sw_event+0x31c/0x570 kernel/events/core.c:8082
 __perf_sw_event+0x51/0xa0 kernel/events/core.c:8094
 perf_sw_event include/linux/perf_event.h:1064 [inline]
 __do_page_fault+0x7a6/0xe90 arch/x86/mm/fault.c:1431
 do_page_fault+0x71/0x57d arch/x86/mm/fault.c:1465
 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1204
RIP: 0010:copy_user_enhanced_fast_string+0xe/0x20 arch/x86/lib/copy_user_64.S:181
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 0f 1f 00 83
RSP: 0018:ffff88806b83fab8 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000500
RDX: 0000000000001000 RSI: ffff88806f5d2b00 RDI: 00000000205b1000
RBP: ffff88806b83faf0 R08: ffffed100deba600 R09: 0000000000000000
R10: ffffed100deba5ff R11: ffff88806f5d2fff R12: 00000000205b0500
R13: ffff88806f5d2000 R14: 00000000205b1500 R15: 00007ffffffff000
 copy_page_to_iter_iovec lib/iov_iter.c:206 [inline]
 copy_page_to_iter+0x329/0xd50 lib/iov_iter.c:853
 pipe_to_user+0xb4/0x170 fs/splice.c:1238
 splice_from_pipe_feed fs/splice.c:503 [inline]
 __splice_from_pipe+0x391/0x7d0 fs/splice.c:627
 vmsplice_to_user fs/splice.c:1262 [inline]
 do_vmsplice.part.0+0x249/0x2b0 fs/splice.c:1340
 do_vmsplice fs/splice.c:1334 [inline]
 __do_sys_vmsplice+0x1b9/0x210 fs/splice.c:1361
 __se_sys_vmsplice fs/splice.c:1343 [inline]
 __x64_sys_vmsplice+0x97/0xf0 fs/splice.c:1343
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4598e9
Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f27593efc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000116
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00000000004598e9
RDX: 0000000000000001 RSI: 0000000020000000 RDI: 0000000000000005
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f27593f06d4
R13: 00000000004c90c8 R14: 00000000004e0338 R15: 00000000ffffffff