=============================== [ INFO: suspicious RCU usage. ] 4.9.155+ #27 Not tainted ------------------------------- net/ipv6/ip6_fib.c:1470 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 0 4 locks held by swapper/0/0: #0: (((&net->ipv6.ip6_fib_timer))){+.-...}, at: [] lockdep_copy_map include/linux/lockdep.h:165 [inline] #0: (((&net->ipv6.ip6_fib_timer))){+.-...}, at: [] call_timer_fn+0xde/0x6d0 kernel/time/timer.c:1309 #1: (&(&net->ipv6.fib6_gc_lock)->rlock){+.-...}, at: [] spin_lock_bh include/linux/spinlock.h:307 [inline] #1: (&(&net->ipv6.fib6_gc_lock)->rlock){+.-...}, at: [] fib6_run_gc+0xa2/0x2e0 net/ipv6/ip6_fib.c:1816 #2: (rcu_read_lock){......}, at: [] __fib6_clean_all+0x0/0x230 net/ipv6/ip6_fib.c:1703 #3: (&tb->tb6_lock){++--..}, at: [] __fib6_clean_all+0xe3/0x230 net/ipv6/ip6_fib.c:1717 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.155+ #27 ffff8801db607890 ffffffff81b47871 ffff8801c5839180 0000000000000000 0000000000000002 00000000000005be ffffffff8302d180 ffff8801db6078c0 ffffffff813fed99 ffff8801db607ae0 dffffc0000000000 00000000ffffffff Call Trace: [ 670.642118] [] __dump_stack lib/dump_stack.c:15 [inline] [ 670.642118] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] lockdep_rcu_suspicious.cold+0x10a/0x149 kernel/locking/lockdep.c:4455 [] fib6_del+0x81f/0xb20 net/ipv6/ip6_fib.c:1470 [] fib6_clean_node+0x29c/0x4d0 net/ipv6/ip6_fib.c:1657 [] fib6_walk_continue+0x3e0/0x630 net/ipv6/ip6_fib.c:1583 [] fib6_walk+0x9d/0xf0 net/ipv6/ip6_fib.c:1628 [] fib6_clean_tree+0xe7/0x120 net/ipv6/ip6_fib.c:1702 [] __fib6_clean_all+0xfb/0x230 net/ipv6/ip6_fib.c:1718 [] fib6_clean_all net/ipv6/ip6_fib.c:1729 [inline] [] fib6_run_gc+0x124/0x2e0 net/ipv6/ip6_fib.c:1826 [] fib6_gc_timer_cb+0x1d/0x30 net/ipv6/ip6_fib.c:1841 [] call_timer_fn+0x167/0x6d0 kernel/time/timer.c:1319 [] expire_timers+0x25b/0x5c0 kernel/time/timer.c:1359 [] __run_timers kernel/time/timer.c:1674 [inline] [] run_timer_softirq+0x1ff/0x620 kernel/time/timer.c:1687 [] __do_softirq+0x22d/0x964 kernel/softirq.c:288 [] invoke_softirq kernel/softirq.c:368 [inline] [] irq_exit+0x119/0x160 kernel/softirq.c:409 [] exiting_irq arch/x86/include/asm/apic.h:669 [inline] [] smp_apic_timer_interrupt+0x7e/0xb0 arch/x86/kernel/apic/apic.c:962 [] apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:648 [ 670.920061] [] ? native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:56 [] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:428 [] default_idle_call+0x36/0x60 kernel/sched/idle.c:97 [] cpuidle_idle_call kernel/sched/idle.c:155 [inline] [] cpu_idle_loop kernel/sched/idle.c:248 [inline] [] cpu_startup_entry+0x283/0x3a0 kernel/sched/idle.c:303 [] rest_init+0x18b/0x194 init/main.c:409 [] start_kernel+0x619/0x64d init/main.c:664 [] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196 [] x86_64_start_kernel+0x137/0x15a arch/x86/kernel/head64.c:177