=============================== [ INFO: suspicious RCU usage. ] 4.4.174+ #4 Not tainted ------------------------------- net/ipv6/ip6_fib.c:1465 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 5 locks held by udevd/17630: #0: (remove_cache_srcu){......}, at: [] srcu_read_lock include/linux/srcu.h:222 [inline] #0: (remove_cache_srcu){......}, at: [] quarantine_reduce+0x95/0x1d0 mm/kasan/quarantine.c:232 #1: (((&net->ipv6.ip6_fib_timer))){+.-...}, at: [] lockdep_copy_map include/linux/lockdep.h:165 [inline] #1: (((&net->ipv6.ip6_fib_timer))){+.-...}, at: [] call_timer_fn+0xde/0x850 kernel/time/timer.c:1175 #2: (fib6_gc_lock){+.-...}, at: [] spin_lock_bh include/linux/spinlock.h:307 [inline] #2: (fib6_gc_lock){+.-...}, at: [] fib6_run_gc+0x3a/0x230 net/ipv6/ip6_fib.c:1811 #3: (rcu_read_lock){......}, at: [] __fib6_clean_all+0x0/0x240 net/ipv6/ip6_fib.c:1698 #4: (&tb->tb6_lock){++--..}, at: [] __fib6_clean_all+0xe8/0x240 net/ipv6/ip6_fib.c:1712 stack backtrace: CPU: 0 PID: 17630 Comm: udevd Not tainted 4.4.174+ #4 0000000000000000 bea4dfd3df32067b ffff8801db607940 ffffffff81aad1a1 ffff8801d85b2000 0000000000000000 0000000000000001 00000000000005b9 ffff8801bd604740 ffff8801db607970 ffffffff813ab7d6 ffff8801db607b90 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] lockdep_rcu_suspicious.cold+0x10a/0x149 kernel/locking/lockdep.c:4305 [] fib6_del+0x7ea/0xae0 net/ipv6/ip6_fib.c:1465 [] fib6_clean_node+0x29c/0x500 net/ipv6/ip6_fib.c:1652 [] fib6_walk_continue+0x3e0/0x630 net/ipv6/ip6_fib.c:1578 [] fib6_walk+0x91/0xe0 net/ipv6/ip6_fib.c:1623 [] fib6_clean_tree+0xe8/0x120 net/ipv6/ip6_fib.c:1697 [] __fib6_clean_all+0x100/0x240 net/ipv6/ip6_fib.c:1713 [] fib6_clean_all net/ipv6/ip6_fib.c:1724 [inline] [] fib6_run_gc+0xaf/0x230 net/ipv6/ip6_fib.c:1821 [] fib6_gc_timer_cb+0x1d/0x30 net/ipv6/ip6_fib.c:1836 [] call_timer_fn+0x18d/0x850 kernel/time/timer.c:1185 [] __run_timers kernel/time/timer.c:1261 [inline] [] run_timer_softirq+0x51f/0xb70 kernel/time/timer.c:1444 [] __do_softirq+0x226/0xa3f kernel/softirq.c:273 [] invoke_softirq kernel/softirq.c:350 [inline] [] irq_exit+0x10a/0x150 kernel/softirq.c:391 [] exiting_irq arch/x86/include/asm/apic.h:652 [inline] [] smp_apic_timer_interrupt+0x7e/0xb0 arch/x86/kernel/apic/apic.c:926 [] apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:768 [] ? arch_local_irq_restore arch/x86/include/asm/paravirt.h:812 [inline] [] ? put_cpu_partial+0x10d/0x1a0 mm/slub.c:2154 [] __slab_free+0x31f/0x4f0 mm/slub.c:2755 [] do_slab_free mm/slub.c:2851 [inline] [] ___cache_free+0xa7/0xc0 mm/slub.c:2872 [] qlink_free mm/kasan/quarantine.c:147 [inline] [] qlist_free_all+0x4a/0xc0 mm/kasan/quarantine.c:166 [] quarantine_reduce+0x18f/0x1d0 mm/kasan/quarantine.c:259 [] kasan_kmalloc+0xa0/0xd0 mm/kasan/kasan.c:601 [] kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:554 [] slab_post_alloc_hook mm/slub.c:1349 [inline] [] slab_alloc_node mm/slub.c:2615 [inline] [] slab_alloc mm/slub.c:2623 [inline] [] kmem_cache_alloc+0xdc/0x2c0 mm/slub.c:2628 [] getname_flags+0xcc/0x550 fs/namei.c:135 [] getname fs/namei.c:206 [inline] [] SYSC_symlinkat fs/namei.c:4062 [inline] [] SyS_symlinkat+0x88/0x240 fs/namei.c:4053 [] SYSC_symlink fs/namei.c:4086 [inline] [] SyS_symlink+0x23/0x30 fs/namei.c:4084 [] entry_SYSCALL_64_fastpath+0x1e/0x9a netlink: 8 bytes leftover after parsing attributes in process `syz-executor.4'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.4'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.4'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.4'. audit: type=1400 audit(1550253627.947:3573): avc: denied { create } for pid=11308 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0 netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. audit: type=1400 audit(1550253628.657:3574): avc: denied { create } for pid=11308 comm="syz-executor.4" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=0 netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 9 bytes leftover after parsing attributes in process `syz-executor.4'. netlink: 9 bytes leftover after parsing attributes in process `syz-executor.4'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'.