rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7449/1:b..l P5427/1:b..l (detected by 1, t=10502 jiffies, g=26717, q=358) task:kworker/u4:15 state:R running task stack:23584 pid: 5427 ppid: 2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6780 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+0x1f2/0x3f0 kernel/locking/lockdep.c:5627 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 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 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b RSP: 0018:ffffc900032b7900 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: e0fd22e8f277f900 RDX: 0000000000000000 RSI: ffffffff8a0b2460 RDI: ffffffff8a59a740 RBP: ffffc900032b7a20 R08: dffffc0000000000 R09: fffffbfff1ff3619 R10: fffffbfff1ff3619 R11: 1ffffffff1ff3618 R12: ffffffff8c11bfa0 R13: 1ffff92000656f2c R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312 rcu_read_lock include/linux/rcupdate.h:739 [inline] inet_twsk_purge+0x119/0x810 net/ipv4/inet_timewait_sock.c:268 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x77b/0xb80 net/core/net_namespace.c:635 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 task:syz.1.593 state:R running task stack:26880 pid: 7449 ppid: 7099 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6780 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:rcu_is_watching+0x63/0xa0 kernel/rcu/tree.c:1124 Code: 89 f7 e8 50 9d 59 00 48 c7 c3 c8 b2 03 00 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 2b 8b 03 65 ff 0d c5 d2 9e 7e <74> 08 24 01 5b 41 5e 41 5f c3 e8 86 dd 9c ff eb f1 48 c7 c7 20 0c RSP: 0018:ffffc90002daf590 EFLAGS: 00000286 RAX: 00000000001cc9d7 RBX: ffff8880b903b2c8 RCX: ddfb1e71f8d53f00 RDX: 0000000000000001 RSI: ffffffff8a59a720 RDI: ffffffff8a59a6e0 RBP: 1ffffd4000327669 R08: dffffc0000000000 R09: fffffbfff1ad157e R10: fffffbfff1ad157e R11: 1ffffffff1ad157d R12: dffffc0000000000 R13: 1ffff11004899802 R14: ffffffff8bbaf810 R15: dffffc0000000000 rcu_read_unlock include/linux/rcupdate.h:768 [inline] get_mem_cgroup_from_objcg+0xcf/0x120 mm/memcontrol.c:2817 uncharge_page+0x140/0x490 mm/memcontrol.c:6931 __mem_cgroup_uncharge_list+0x6c/0xc0 mm/memcontrol.c:7004 mem_cgroup_uncharge_list include/linux/memcontrol.h:720 [inline] release_pages+0x1843/0x1bb0 mm/swap.c:962 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:240 [inline] tlb_flush_mmu mm/mmu_gather.c:247 [inline] tlb_finish_mmu+0x164/0x2e0 mm/mmu_gather.c:338 exit_mmap+0x3a6/0x5f0 mm/mmap.c:3206 __mmput+0x115/0x3b0 kernel/fork.c:1127 exit_mm+0x567/0x6c0 kernel/exit.c:550 do_exit+0x599/0x20a0 kernel/exit.c:861 do_group_exit+0x12e/0x300 kernel/exit.c:996 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7effb3086929 RSP: 002b:00007effb0eee038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: 0000000000224000 RBX: 00007effb32adfa0 RCX: 00007effb3086929 RDX: 00000000fffffd2c RSI: 0000200000000000 RDI: 0000000000000007 RBP: 00007effb3108b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007effb32adfa0 R15: 00007ffdc188e5b8 rcu: rcu_preempt kthread starved for 10152 jiffies! g26717 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:28032 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376 schedule+0x11b/0x1e0 kernel/sched/core.c:6459 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 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 default_idle+0xb/0x10 arch/x86/kernel/process.c:722