=============================== [ INFO: suspicious RCU usage. ] 4.9.118-g47b77b8 #20 Not tainted ------------------------------- net/ipv6/ip6_fib.c:1471 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 0 6 locks held by kworker/u4:11/29925: #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: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70 #4: (rcu_read_lock){......}, at: [] __fib6_clean_all+0x0/0x220 net/ipv6/ip6_fib.c:1703 #5: (&tb->tb6_lock){++--..}, at: [] __fib6_clean_all+0xe0/0x220 net/ipv6/ip6_fib.c:1717 stack backtrace: CPU: 0 PID: 29925 Comm: kworker/u4:11 Not tainted 4.9.118-g47b77b8 #20 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net ffff8801a6f9f0b8 ffffffff81eb4b89 ffff8801a9d83000 0000000000000000 0000000000000002 ffffffff84167780 ffffed0034df3e66 ffff8801a6f9f0e8 ffffffff814262c0 ffff8801cd7e4380 ffff8801a6f9f2e0 ffff8801cd7e4380 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] lockdep_rcu_suspicious.cold.48+0x110/0x141 kernel/locking/lockdep.c:4455 [] fib6_del+0x773/0xa20 net/ipv6/ip6_fib.c:1470 [] fib6_clean_node+0x220/0x4c0 net/ipv6/ip6_fib.c:1657 [] fib6_walk_continue+0x3e5/0x640 net/ipv6/ip6_fib.c:1583 [] fib6_walk+0xd9/0x150 net/ipv6/ip6_fib.c:1628 [] fib6_clean_tree+0xd3/0x110 net/ipv6/ip6_fib.c:1702 [] __fib6_clean_all+0xf9/0x220 net/ipv6/ip6_fib.c:1718 [] fib6_clean_all+0x27/0x30 net/ipv6/ip6_fib.c:1729 [] rt6_ifdown+0xa1/0x7f0 net/ipv6/route.c:2716 [] addrconf_ifdown+0xd0/0x10e0 net/ipv6/addrconf.c:3569 [] addrconf_notify+0x7f8/0x2160 net/ipv6/addrconf.c:3493 [] notifier_call_chain+0xb4/0x1d0 kernel/notifier.c:93 [] __raw_notifier_call_chain kernel/notifier.c:394 [inline] [] raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401 [] call_netdevice_notifiers_info+0x55/0x70 net/core/dev.c:1647 [] call_netdevice_notifiers net/core/dev.c:1663 [inline] [] dev_close_many+0x252/0x380 net/core/dev.c:1456 [] rollback_registered_many+0x268/0x920 net/core/dev.c:6810 [] unregister_netdevice_many.part.106+0x1b/0x110 net/core/dev.c:7879 [] unregister_netdevice_many net/core/dev.c:7878 [inline] [] default_device_exit_batch+0x353/0x410 net/core/dev.c:8337 [] 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 FAT-fs (loop4): Unrecognized mount option "nnonumtail=1" or missing value FAT-fs (loop4): Unrecognized mount option "nnonumtail=1" or missing value EXT2-fs (loop5): error: can't find an ext2 filesystem on dev loop5.