=============================== [ INFO: suspicious RCU usage. ] 4.9.113-g47bbcd6 #10 Not tainted ------------------------------- kernel/rcu/tree_plugin.h:678 Illegal synchronize_rcu() in RCU read-side critical section! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 0 5 locks held by kworker/u4:1/22: #0: ("%s""netns"){.+.+.+}, at: [] work_static include/linux/workqueue.h:186 [inline] #0: ("%s""netns"){.+.+.+}, at: [] set_work_data kernel/workqueue.c:617 [inline] #0: ("%s""netns"){.+.+.+}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: ("%s""netns"){.+.+.+}, at: [] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085 #1: (net_cleanup_work){+.+.+.}, at: [] process_one_work+0x728/0x1500 kernel/workqueue.c:2089 #2: (net_mutex){+.+.+.}, at: [] cleanup_net+0x13f/0x630 net/core/net_namespace.c:439 #3: (rcu_read_lock){......}, at: [] __read_once_size include/linux/compiler.h:243 [inline] #3: (rcu_read_lock){......}, at: [] inet_twsk_purge+0x7a/0x590 net/ipv4/inet_timewait_sock.c:275 #4: (rcu_callback){......}, at: [] __rcu_reclaim kernel/rcu/rcu.h:108 [inline] #4: (rcu_callback){......}, at: [] rcu_do_batch kernel/rcu/tree.c:2789 [inline] #4: (rcu_callback){......}, at: [] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline] #4: (rcu_callback){......}, at: [] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline] #4: (rcu_callback){......}, at: [] rcu_process_callbacks+0x98e/0x12b0 kernel/rcu/tree.c:3037 stack backtrace: CPU: 1 PID: 22 Comm: kworker/u4:1 Not tainted 4.9.113-g47bbcd6 #10 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net ffff8801db307d60 ffffffff81eb32a9 ffff8801d9ae9800 0000000000000000 0000000000000002 ffffffff83c6df20 ffff8801bd23d058 ffff8801db307d90 ffffffff814260f0 ffff8801bd23cf00 ffff8801a888dd48 ffff8801a888d548 Call Trace: [ 192.699305] [] __dump_stack lib/dump_stack.c:15 [inline] [ 192.699305] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] lockdep_rcu_suspicious.cold.48+0x110/0x141 kernel/locking/lockdep.c:4455 [] synchronize_rcu+0x68/0x90 kernel/rcu/tree_plugin.h:675 [] __l2tp_session_unhash+0x38a/0x520 net/l2tp/l2tp_core.c:1796 [] l2tp_tunnel_closeall+0x1f7/0x350 net/l2tp/l2tp_core.c:1364 [] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1324 [] __sk_destruct+0x55/0x590 net/core/sock.c:1428 [] __rcu_reclaim kernel/rcu/rcu.h:118 [inline] [] rcu_do_batch kernel/rcu/tree.c:2789 [inline] [] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline] [] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline] [] rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037 [] __do_softirq+0x20b/0x937 kernel/softirq.c:284 [] invoke_softirq kernel/softirq.c:364 [inline] [] irq_exit+0x147/0x190 kernel/softirq.c:405 [] exiting_irq arch/x86/include/asm/apic.h:659 [inline] [] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:960 [] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648 [ 192.812717] [] ? check_preemption_disabled+0x1/0x170 lib/smp_processor_id.c:12 [] __rcu_is_watching kernel/rcu/tree.c:1053 [inline] [] rcu_is_watching+0x15/0xa0 kernel/rcu/tree.c:1067 [] rcu_read_lock include/linux/rcupdate.h:876 [inline] [] inet_twsk_purge+0x407/0x590 net/ipv4/inet_timewait_sock.c:273 [] tcpv6_net_exit_batch+0x21/0x30 net/ipv6/tcp_ipv6.c:1967 [] ops_exit_list.isra.6+0x105/0x160 net/core/net_namespace.c:139 [] cleanup_net+0x321/0x630 net/core/net_namespace.c:473 [] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092 [] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 ODEBUG: object ffff8801db307ce8 is NOT on stack ffff8801d9bf0000, but annotated ------------[ cut here ]------------ WARNING: CPU: 1 PID: 22 at lib/debugobjects.c:303 debug_object_is_on_stack lib/debugobjects.c:303 [inline] WARNING: CPU: 1 PID: 22 at lib/debugobjects.c:303 __debug_object_init.cold.10+0x6b/0x2b0 lib/debugobjects.c:329