rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9552/1:b..l
	(detected by 0, t=10502 jiffies, g=31913, q=184)
task:syz.4.2504      state:R  running task     stack:25432 pid: 9552 ppid:  5823 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780
 irqentry_exit+0x53/0x80 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:768 [inline]
RIP: 0010:count_memcg_event_mm+0x301/0x3e0 include/linux/memcontrol.h:1082
Code: 89 fe ff ff e8 e0 41 c7 ff eb 1f e8 d9 41 c7 ff e8 e4 ed 79 08 4d 85 ed 74 89 e8 ca 41 c7 ff fb 49 bd 00 00 00 00 00 fc ff df <e8> 6a f3 79 08 89 c3 31 ff 89 c6 e8 0f 45 c7 ff 85 db 74 10 e8 76
RSP: 0018:ffffc90002fb75c0 EFLAGS: 00000287
RAX: ffffffff81b91f96 RBX: 0000000000000000 RCX: 0000000000040000
RDX: ffffc9000f958000 RSI: 00000000000389fb RDI: 00000000000389fc
RBP: ffffc90002fb7690 R08: ffffffff81b91f0b R09: fffffbfff1f8e01f
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888074e60000
R13: dffffc0000000000 R14: 1ffff920005f6ebc R15: 0000000000000046
 handle_mm_fault+0x161/0x5950 mm/memory.c:4834
 do_user_addr_fault arch/x86/mm/fault.c:1357 [inline]
 handle_page_fault arch/x86/mm/fault.c:1445 [inline]
 exc_page_fault+0x271/0x700 arch/x86/mm/fault.c:1501
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568
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 01 ca c3 0f 1f 80 00 00 00 00 0f 01 cb 83 fa 40 0f 82 70 ff ff ff 89 d1 <f3> a4 31 c0 0f 01 ca c3 66 2e 0f 1f 84 00 00 00 00 00 89 d1 83 f8
RSP: 0018:ffffc90002fb7a70 EFLAGS: 00050206
RAX: ffffffff84073801 RBX: 00000000201cde80 RCX: 0000000000000e80
RDX: 0000000000001000 RSI: ffff88800f55a180 RDI: 00000000201cd000
RBP: ffffc90002fb7cd0 R08: dffffc0000000000 R09: ffffed1001eab600
R10: 0000000000000000 R11: dffffc0000000001 R12: 00000000201cce80
R13: 0000000000001000 R14: ffff88800f55a000 R15: 00007ffffffff000
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
 copyout lib/iov_iter.c:157 [inline]
 copy_page_to_iter_iovec lib/iov_iter.c:228 [inline]
 __copy_page_to_iter lib/iov_iter.c:861 [inline]
 copy_page_to_iter+0x49a/0x10d0 lib/iov_iter.c:889
 process_vm_rw_pages mm/process_vm_access.c:45 [inline]
 process_vm_rw_single_vec mm/process_vm_access.c:117 [inline]
 process_vm_rw_core mm/process_vm_access.c:215 [inline]
 process_vm_rw+0x886/0xcc0 mm/process_vm_access.c:283
 __do_sys_process_vm_readv mm/process_vm_access.c:295 [inline]
 __se_sys_process_vm_readv mm/process_vm_access.c:291 [inline]
 __x64_sys_process_vm_readv+0xdc/0xf0 mm/process_vm_access.c:291
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f44a083a9f9
RSP: 002b:00007f449ecb9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000136
RAX: ffffffffffffffda RBX: 00007f44a09c8f80 RCX: 00007f44a083a9f9
RDX: 0000000000000002 RSI: 0000000020008400 RDI: 0000000000000293
RBP: 00007f44a08a88ee R08: 0000000000000286 R09: 0000000000000000
R10: 0000000020008640 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f44a09c8f80 R15: 00007ffc6cd898a8
 </TASK>
rcu: rcu_preempt kthread starved for 9807 jiffies! g31913 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27256 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:108 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:562