rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P7109/1:b..l P12969/1:b..l
	(detected by 0, t=10502 jiffies, g=50341, q=187)
task:syz.6.2561      state:R  running task     stack:28240 pid:12969 ppid:  5260 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681
RIP: 0010:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0000:ffffc900037cfb40 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 4b23860866f18f00
RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f800
RBP: ffffc900037cfc50 R08: dffffc0000000000 R09: 1ffffffff203a618
R10: dffffc0000000000 R11: fffffbfff203a619 R12: ffffffff8c31eaa0
R13: 1ffff920006f9f74 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire+0x20/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 percpu_ref_put_many include/linux/percpu-refcount.h:317 [inline]
 percpu_ref_put+0x16/0x150 include/linux/percpu-refcount.h:338
 css_put include/linux/cgroup.h:405 [inline]
 __mem_cgroup_charge+0x52/0x80 mm/memcontrol.c:6802
 mem_cgroup_charge include/linux/memcontrol.h:700 [inline]
 do_anonymous_page mm/memory.c:3842 [inline]
 handle_pte_fault mm/memory.c:4648 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x23ff/0x4410 mm/memory.c:4883
 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1355
 handle_page_fault arch/x86/mm/fault.c:1443 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f95b8962bdf
RSP: 002b:00007f95b6bcbff0 EFLAGS: 00010246
RAX: 00007f95b6bcc0d0 RBX: 0000000000020000 RCX: 00007f95b6bcbff0
RDX: 00007f95b8a669d3 RSI: 0000000000000023 RDI: 00007f95b6bcc0d0
RBP: 00007f95b6bad000 R08: 0000000000000000 R09: 00007fff64537177
R10: 0000000000000008 R11: 0000000000000202 R12: 00007f95b6bcc0d0
R13: 000000000000006e R14: 00007fff64537090 R15: 00007fff64537178
 </TASK>
task:kworker/u4:11   state:R  running task     stack:22096 pid: 7109 ppid:     2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:91 [inline]
RIP: 0010:lock_acquire+0x11f/0x400 kernel/locking/lockdep.c:5599
Code: 65 8b 05 44 77 a5 7e 85 c0 0f 85 43 01 00 00 65 4c 8b 35 b4 6d a5 7e 49 81 c6 ec 0a 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 <84> c0 0f 85 08 02 00 00 41 83 3e 00 0f 85 16 01 00 00 43 c6 44 3d
RSP: 0018:ffffc9000380f900 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: 0000000000000000 RCX: fc5f0d2f72d7e200
RDX: 0000000000000000 RSI: ffffffff8a79f7e0 RDI: ffffffff8a79f7a0
RBP: ffffc9000380fa20 R08: ffffffff8d89dc2f R09: 1ffffffff1b13b85
R10: dffffc0000000000 R11: fffffbfff1b13b86 R12: ffffffff8c31eaa0
R13: 1ffff92000701f2c R14: ffff88807396642c R15: dffffc0000000000
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 inet_twsk_purge+0x119/0x840 net/ipv4/inet_timewait_sock.c:268
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x791/0xba0 net/core/net_namespace.c:635
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: rcu_preempt kthread starved for 9702 jiffies! g50341 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:27536 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 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 default_idle+0xb/0x10 arch/x86/kernel/process.c:729