rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4200/1:b..l P4615/1:b..l P154/1:b..l (detected by 0, t=10502 jiffies, g=10609, q=315) task:kworker/u4:2 state:R running task stack:22152 pid: 154 ppid: 2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_irq+0xb1/0x150 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: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:ffffc90001fe7900 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 42f36c1273ba3c00 RDX: 0000000000000000 RSI: ffffffff8a0b2e80 RDI: ffffffff8a59e800 RBP: ffffc90001fe7a20 R08: dffffc0000000000 R09: fffffbfff1ff5419 R10: fffffbfff1ff5419 R11: 1ffffffff1ff5418 R12: ffffffff8c11c720 R13: 1ffff920003fcf2c R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] inet_twsk_purge+0x119/0x810 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:kworker/u4:8 state:R running task stack:26368 pid: 4615 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_irq+0xb1/0x150 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:__preempt_count_add kernel/rcu/tree.c:1119 [inline] RIP: 0010:rcu_is_watching+0x4/0xa0 kernel/rcu/tree.c:1122 Code: 8d 65 e8 5b 41 5e 41 5f 5d c3 e8 37 36 3e 08 41 f7 c7 00 02 00 00 75 b8 eb b7 e8 17 36 3e 08 0f 1f 80 00 00 00 00 41 57 41 56 <53> 65 ff 05 8c be 9e 7e e8 0f 46 3e 08 89 c3 83 f8 08 73 5c 49 bf RSP: 0018:ffffc9000390fbc8 EFLAGS: 00000202 RAX: ffffffff897729c3 RBX: dffffc0000000000 RCX: ffff8880236bbb80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff1ff5419 R10: fffffbfff1ff5419 R11: 1ffffffff1ff5418 R12: 000000000000008a R13: fffffffffffffe38 R14: ffff8880631ecc80 R15: ffff88802a012490 rcu_read_unlock include/linux/rcupdate.h:769 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:416 [inline] batadv_nc_worker+0x1dc/0x5c0 net/batman-adv/network-coding.c:723 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:udevd state:R running task stack:25056 pid: 4200 ppid: 3560 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0xf6/0x100 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:419 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x11b/0x180 kernel/sched/wait.c:205 sock_def_readable+0x136/0x250 net/core/sock.c:3101 unix_dgram_sendmsg+0x11ed/0x1890 net/unix/af_unix.c:1946 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] sock_write_iter+0x29c/0x380 net/socket.c:1089 call_write_iter include/linux/fs.h:2173 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x712/0xd00 fs/read_write.c:594 ksys_write+0x14d/0x250 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7effae16e407 RSP: 002b:00007ffdcc6246c0 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007effae080880 RCX: 00007effae16e407 RDX: 0000000000000000 RSI: 00007ffdcc624767 RDI: 000000000000000a RBP: 000000000000000a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007effae0806e8 R13: 0000000000000000 R14: 0000000000000000 R15: 00005620c2bedba0 rcu: rcu_preempt kthread starved for 9795 jiffies! g10609 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:27008 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 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 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