rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3668/1:b..l
	(detected by 1, t=10502 jiffies, g=4529, q=582)
task:syz.1.2         state:R  running task     stack:25592 pid: 3668 ppid:  3573 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:__sanitizer_cov_trace_const_cmp4+0x0/0x80 kernel/kcov.c:285
Code: 39 d0 77 22 89 f8 89 f6 48 c7 44 0a 08 03 00 00 00 48 89 44 0a 10 48 89 74 0a 18 4c 89 44 0a 20 49 ff c1 4c 89 09 c3 0f 1f 00 <4c> 8b 04 24 65 48 8b 15 f4 0a 82 7e 65 8b 05 f5 0a 82 7e a9 00 01
RSP: 0018:ffffc900030f74c0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88801e798000 RCX: 0000000080000000
RDX: ffff88801e798000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff81c3a908 R09: fffffbfff1f8e019
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff888076776000 R15: 00fff00000000000
 task_css include/linux/cgroup.h:496 [inline]
 blk_cgroup_congested include/linux/blk-cgroup.h:282 [inline]
 __cgroup_throttle_swaprate+0x1af/0x540 mm/swapfile.c:3809
 cgroup_throttle_swaprate include/linux/swap.h:728 [inline]
 wp_page_copy+0x4e4/0x2070 mm/memory.c:3050
 handle_pte_fault mm/memory.c:4639 [inline]
 __handle_mm_fault mm/memory.c:4756 [inline]
 handle_mm_fault+0x2a3d/0x5950 mm/memory.c:4854
 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:ffffc900030f7a70 EFLAGS: 00050206
RAX: ffffffff84073801 RBX: 0000000020481ec0 RCX: 0000000000000ec0
RDX: 0000000000001000 RSI: ffff88800f55a140 RDI: 0000000020481000
RBP: ffffc900030f7cd0 R08: dffffc0000000000 R09: ffffed1001eab600
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000020480ec0
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: 0033:0x7fbac04c3e79
RSP: 002b:00007fbabe940038 EFLAGS: 00000246 ORIG_RAX: 0000000000000136
RAX: ffffffffffffffda RBX: 00007fbac065ff80 RCX: 00007fbac04c3e79
RDX: 0000000000000002 RSI: 0000000020008400 RDI: 0000000000000003
RBP: 00007fbac0531916 R08: 0000000000000286 R09: 0000000000000000
R10: 0000000020008640 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fbac065ff80 R15: 00007fffff46caa8
 </TASK>
rcu: rcu_preempt kthread starved for 9852 jiffies! g4529 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:26712 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 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:108 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:562