syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=e62/1/0x4000000000000002 softirq=25067/25068 fqs=5246 
rcu: 	 (t=10500 jiffies g=36265 q=1377)
NMI backtrace for cpu 0
CPU: 0 PID: 13664 Comm: syz-executor.1 Not tainted 5.1.0-rc4+ #61
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+0x1be/0x236 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.c:1223
 print_cpu_stall kernel/rcu/tree.c:1360 [inline]
 check_cpu_stall kernel/rcu/tree.c:1434 [inline]
 rcu_pending kernel/rcu/tree.c:3103 [inline]
 rcu_sched_clock_irq.cold+0x500/0xa4a kernel/rcu/tree.c:2544
 update_process_times+0x32/0x80 kernel/time/timer.c:1635
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x33e/0xde0 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline]
 smp_apic_timer_interrupt+0x120/0x570 arch/x86/kernel/apic/apic.c:1060
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:kasan_mem_to_shadow include/linux/kasan.h:29 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:135 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:166 [inline]
RIP: 0010:check_memory_region_inline mm/kasan/generic.c:182 [inline]
RIP: 0010:check_memory_region+0x41/0x190 mm/kasan/generic.c:191
Code: 48 39 c7 48 89 e5 41 55 41 54 53 0f 86 f6 00 00 00 4c 8d 5c 37 ff 49 89 f8 48 b8 00 00 00 00 00 fc ff df 4d 89 da 49 c1 e8 03 <4d> 8d 24 00 49 c1 ea 03 49 01 c2 4c 89 e0 49 8d 5a 01 49 89 d9 4d
RSP: 0018:ffff888085ef7158 EFLAGS: 00000a06 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: 0000000000000dc8 RCX: ffffffff81861a06
RDX: 0000000000000000 RSI: 0000000000000010 RDI: ffff888085ef72f8
RBP: ffff888085ef7170 R08: 1ffff11010bdee5f R09: ffffed101328d8c0
R10: ffff888085ef7307 R11: ffff888085ef7307 R12: 0000000000000010
R13: ffff888095d6f238 R14: ffff888085ef72f8 R15: ffff888085ef7510
 memcpy+0x24/0x50 mm/kasan/common.c:132
 memcpy include/linux/string.h:355 [inline]
 memcpy_common kernel/events/internal.h:173 [inline]
 __output_copy kernel/events/internal.h:177 [inline]
 perf_output_read_group kernel/events/core.c:6129 [inline]
 perf_output_read+0xe16/0x1390 kernel/events/core.c:6162
 perf_output_sample+0x13b9/0x1a90 kernel/events/core.c:6204
 __perf_event_output kernel/events/core.c:6528 [inline]
 perf_event_output_forward+0x150/0x290 kernel/events/core.c:6542
 __perf_event_overflow+0x144/0x360 kernel/events/core.c:8009
 perf_swevent_overflow+0xaa/0x140 kernel/events/core.c:8085
 perf_swevent_event+0x1f7/0x2f0 kernel/events/core.c:8118
 do_perf_sw_event kernel/events/core.c:8226 [inline]
 ___perf_sw_event+0x31c/0x570 kernel/events/core.c:8257
 __perf_sw_event+0x51/0xa0 kernel/events/core.c:8269
 perf_sw_event include/linux/perf_event.h:1074 [inline]
 do_user_addr_fault arch/x86/mm/fault.c:1516 [inline]
 __do_page_fault+0x747/0xda0 arch/x86/mm/fault.c:1541
 do_page_fault+0x71/0x581 arch/x86/mm/fault.c:1572
 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1143
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:ffff888085ef7b08 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 0000000000001000 RCX: 00000000000001c0
RDX: 0000000000001000 RSI: 0000000020808000 RDI: ffff8880885cce40
RBP: ffff888085ef7b40 R08: ffffed10110b9a00 R09: 0000000000000000
R10: ffffed10110b99ff R11: ffff8880885ccfff R12: 00000000208071c0
R13: ffff8880885cc000 R14: 00000000208081c0 R15: 00007ffffffff000
 copy_page_from_iter_iovec lib/iov_iter.c:294 [inline]
 copy_page_from_iter+0x3ad/0x7d0 lib/iov_iter.c:920
 pipe_write+0x281/0xf30 fs/pipe.c:454
 call_write_iter include/linux/fs.h:1866 [inline]
 new_sync_write+0x4c7/0x760 fs/read_write.c:474
 __vfs_write+0xe4/0x110 fs/read_write.c:487
 vfs_write+0x20c/0x580 fs/read_write.c:549
 ksys_write+0x14f/0x2d0 fs/read_write.c:599
 __do_sys_write fs/read_write.c:611 [inline]
 __se_sys_write fs/read_write.c:608 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:608
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4582f9
Code: ad b8 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 b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f30ef37ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004582f9
RDX: 0000000100000073 RSI: 00000000200001c0 RDI: 0000000000000007
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f30ef37b6d4
R13: 00000000004c406c R14: 00000000004dcdb0 R15: 00000000ffffffff