rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=602/1/0x4000000000000002 softirq=32233/32233 fqs=2 
rcu: 	 (t=10501 jiffies g=44513 q=83)
rcu: rcu_sched kthread starved for 10498 jiffies! g44513 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_sched       R  running task    29144    10      2 0x80000000
Call Trace:
 context_switch /kernel/sched/core.c:2831 [inline]
 __schedule+0x8f5/0x1b80 /kernel/sched/core.c:3472
 schedule+0x7c/0x180 /kernel/sched/core.c:3516
 schedule_timeout+0x367/0xce0 /kernel/time/timer.c:1803
 rcu_gp_fqs_loop /kernel/rcu/tree.c:1948 [inline]
 rcu_gp_kthread+0x7b4/0x11a0 /kernel/rcu/tree.c:2105
 kthread+0x324/0x3e0 /kernel/kthread.c:246
 ret_from_fork+0x24/0x30 /arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 0
CPU: 0 PID: 23483 Comm: syz-executor.2 Not tainted 5.0.0-rc2+ #1
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+0x115/0x167 /lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.4+0x3e/0x76 /lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x11a/0x136 /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+0x16f/0x1bc /kernel/rcu/tree.c:1211
 print_cpu_stall /kernel/rcu/tree.c:1348 [inline]
 check_cpu_stall /kernel/rcu/tree.c:1422 [inline]
 rcu_pending /kernel/rcu/tree.c:3018 [inline]
 rcu_check_callbacks.cold.71+0x4a8/0x7c9 /kernel/rcu/tree.c:2521
 update_process_times+0x2a/0x60 /kernel/time/timer.c:1635
 tick_sched_handle+0x77/0x140 /kernel/time/tick-sched.c:161
 tick_sched_timer+0x37/0xf0 /kernel/time/tick-sched.c:1271
 __run_hrtimer /kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x2f6/0xa60 /kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x2b5/0x720 /kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt /arch/x86/kernel/apic/apic.c:1035 [inline]
 smp_apic_timer_interrupt+0xda/0x4c0 /arch/x86/kernel/apic/apic.c:1060
 apic_timer_interrupt+0xf/0x20 /arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:lock_is_held_type+0x15/0x210 /kernel/locking/lockdep.c:3868
Code: 00 e9 63 ff ff ff e8 7a 9e 45 00 eb ad 0f 1f 84 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 55 49 89 fd 41 54 <53> 65 48 8b 1c 25 40 ee 01 00 48 8d bb 3c 08 00 00 48 83 ec 08 48
RSP: 0018:ffff88806deef960 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: ffff888089a96740 RCX: ffffffff8154e0c1
RDX: 1ffffffff10243ae RSI: 00000000ffffffff RDI: ffffffff881bb1d8
RBP: ffff88806deef970 R08: ffffed1015d45b90 R09: ffffed1015d45b8f
R10: ffffed1015d45b8f R11: ffff8880aea2dc7b R12: ffff8880a9745200
R13: ffffffff881bb1d8 R14: 000000002002e080 R15: ffff8880913e7528
 lock_is_held /./include/linux/lockdep.h:337 [inline]
 task_css /./include/linux/cgroup.h:479 [inline]
 mem_cgroup_from_task+0x9e/0x130 /mm/memcontrol.c:815
 count_memcg_event_mm /./include/linux/memcontrol.h:763 [inline]
 handle_mm_fault+0x135/0x8b0 /mm/memory.c:3928
 do_user_addr_fault /arch/x86/mm/fault.c:1475 [inline]
 __do_page_fault+0x3ee/0x9e0 /arch/x86/mm/fault.c:1541
 do_page_fault+0x64/0x386 /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:ffff88806deefb48 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 000000002002e080 RCX: 0000000000001000
RDX: 0000000000001000 RSI: 000000002002e080 RDI: ffff88809d06a000
RBP: ffff88806deefb70 R08: 0000000000000000 R09: 0000000000000040
R10: ffffed1013a0d5ff R11: ffff88809d06afff R12: 0000000000001000
R13: ffff88809d06a000 R14: ffff888092e22480 R15: ffff88809d06a000
 copy_from_user /./include/linux/uaccess.h:144 [inline]
 mem_rw.isra.18+0x1de/0x3a0 /fs/proc/base.c:824
 mem_write+0x3d/0x70 /fs/proc/base.c:863
 __vfs_write+0xe3/0x970 /fs/read_write.c:485
 vfs_write+0x150/0x4e0 /fs/read_write.c:549
 ksys_write+0xcd/0x1b0 /fs/read_write.c:598
 __do_sys_write /fs/read_write.c:610 [inline]
 __se_sys_write /fs/read_write.c:607 [inline]
 __x64_sys_write+0x6e/0xb0 /fs/read_write.c:607
 do_syscall_64+0xd0/0x4d0 /arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459819
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:00007f3b9dd04c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459819
RDX: 000000002000008f RSI: 0000000020000080 RDI: 0000000000000005
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3b9dd056d4
R13: 00000000004c9492 R14: 00000000004e0660 R15: 00000000ffffffff