syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4724/1:b..l
	(detected by 0, t=10502 jiffies, g=9773, q=108)
task:syz.3.120       state:R  running task     stack:26424 pid: 4724 ppid:  4176 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6777
 irqentry_exit+0x53/0x80 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:lock_release+0x156/0x9a0 kernel/locking/lockdep.c:5639
Code: 00 00 4c 89 f3 48 c1 eb 03 42 80 3c 3b 00 74 08 4c 89 f7 e8 ec 79 67 00 4c 89 6c 24 50 48 c7 84 24 b0 00 00 00 00 00 00 00 9c <8f> 84 24 b0 00 00 00 42 80 3c 3b 00 74 08 4c 89 f7 e8 44 79 67 00
RSP: 0018:ffffc900032ef7f8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 1ffff9200065df16 RCX: ffffffff8162f3e8
RDX: 0000000000000000 RSI: ffffffff8af9f2a0 RDI: ffffffff8af9f260
RBP: ffffc900032ef930 R08: dffffc0000000000 R09: fffffbfff1c150ee
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff9200065df0c
R13: ffffffff81cfdad0 R14: ffffc900032ef8b0 R15: dffffc0000000000
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 percpu_ref_tryget_many include/linux/percpu-refcount.h:250 [inline]
 percpu_ref_tryget+0xcd/0x140 include/linux/percpu-refcount.h:266
 obj_cgroup_tryget include/linux/memcontrol.h:800 [inline]
 get_obj_cgroup_from_current mm/memcontrol.c:2927 [inline]
 __memcg_kmem_charge_page+0x256/0x3a0 mm/memcontrol.c:3053
 memcg_kmem_charge_page include/linux/memcontrol.h:1696 [inline]
 memcg_charge_kernel_stack kernel/fork.c:417 [inline]
 dup_task_struct+0x249/0xb60 kernel/fork.c:903
 copy_process+0x5eb/0x3ef0 kernel/fork.c:2036
 kernel_clone+0x210/0x960 kernel/fork.c:2603
 __do_sys_clone3 kernel/fork.c:2878 [inline]
 __se_sys_clone3+0x3e1/0x430 kernel/fork.c:2862
 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: 0033:0x7f3a28f2c649
RSP: 002b:00007ffeeb40b678 EFLAGS: 00000206 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007f3a28eaea30 RCX: 00007f3a28f2c649
RDX: 00007f3a28eaea30 RSI: 0000000000000058 RDI: 00007ffeeb40b6c0
RBP: 00007f3a26d406c0 R08: 00007f3a26d406c0 R09: 00007ffeeb40b7a7
R10: 0000000000000008 R11: 0000000000000206 R12: ffffffffffffffa8
R13: 000000000000006e R14: 00007ffeeb40b6c0 R15: 00007ffeeb40b7a8
 </TASK>
rcu: rcu_preempt kthread starved for 10530 jiffies! g9773 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:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 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