=============================== [ 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 6 locks held by syz-executor.0/2142: #0: (tasklist_lock){.+.+..}, at: [] do_wait+0x2be/0xa00 kernel/exit.c:1515 #1: (rcu_read_lock){......}, at: [] avc_has_perm_noaudit security/selinux/avc.c:1106 [inline] #1: (rcu_read_lock){......}, at: [] avc_has_perm+0xac/0x3a0 security/selinux/avc.c:1146 #2: (((&net->ipv6.ip6_fib_timer))){+.-...}, at: [] lockdep_copy_map include/linux/lockdep.h:165 [inline] #2: (((&net->ipv6.ip6_fib_timer))){+.-...}, at: [] call_timer_fn+0xde/0x850 kernel/time/timer.c:1175 #3: (fib6_gc_lock){+.-...}, at: [] spin_lock_bh include/linux/spinlock.h:307 [inline] #3: (fib6_gc_lock){+.-...}, at: [] fib6_run_gc+0x3a/0x230 net/ipv6/ip6_fib.c:1811 #4: (rcu_read_lock){......}, at: [] __fib6_clean_all+0x0/0x240 net/ipv6/ip6_fib.c:1698 #5: (&tb->tb6_lock){++--..}, at: [] __fib6_clean_all+0xe8/0x240 net/ipv6/ip6_fib.c:1712 stack backtrace: CPU: 0 PID: 2142 Comm: syz-executor.0 Not tainted 4.4.174+ #4 0000000000000000 f7a242dc75b234e5 ffff8801db607940 ffffffff81aad1a1 ffff8800bacaa000 0000000000000000 0000000000000001 00000000000005b9 ffff8800b7c0df00 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 [] ? __read_once_size include/linux/compiler.h:218 [inline] [] ? avc_search_node security/selinux/avc.c:581 [inline] [] ? avc_lookup+0x9a/0x1b0 security/selinux/avc.c:610 [] debug_lockdep_rcu_enabled+0x71/0xa0 kernel/rcu/update.c:242 [] avc_search_node security/selinux/avc.c:581 [inline] [] avc_lookup+0xba/0x1b0 security/selinux/avc.c:610 [] avc_has_perm_noaudit security/selinux/avc.c:1110 [inline] [] avc_has_perm+0x109/0x3a0 security/selinux/avc.c:1146 [] task_has_perm+0x200/0x330 security/selinux/hooks.c:1525 [] selinux_task_wait+0x24/0x30 security/selinux/hooks.c:3763 [] security_task_wait+0x73/0xb0 security/security.c:993 [] wait_consider_task+0x28b/0x35b0 kernel/exit.c:1334 [] do_wait_thread kernel/exit.c:1447 [inline] [] do_wait+0x350/0xa00 kernel/exit.c:1518 [] SYSC_wait4 kernel/exit.c:1649 [inline] [] SyS_wait4+0x144/0x210 kernel/exit.c:1614 [] entry_SYSCALL_64_fastpath+0x1e/0x9a input: syz0 as /devices/virtual/input/input29 input: syz0 as /devices/virtual/input/input30 audit_printk_skb: 9 callbacks suppressed audit: type=1400 audit(1552168849.281:385): avc: denied { create } for pid=8800 comm="syz-executor.3" name="file0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:tape_device_t:s0 tclass=lnk_file permissive=0 input: syz0 as /devices/virtual/input/input31 input: syz0 as /devices/virtual/input/input32 audit: type=1400 audit(1552168849.411:386): avc: denied { create } for pid=8810 comm="syz-executor.3" name="file0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:tape_device_t:s0 tclass=lnk_file permissive=0 input: syz0 as /devices/virtual/input/input33 audit: type=1400 audit(1552168849.541:387): avc: denied { create } for pid=8822 comm="syz-executor.3" name="file0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:tape_device_t:s0 tclass=lnk_file permissive=0 input: syz0 as /devices/virtual/input/input34 input: syz0 as /devices/virtual/input/input35 input: syz0 as /devices/virtual/input/input36 audit: type=1400 audit(1552168850.041:388): avc: denied { create } for pid=8842 comm="syz-executor.3" name="file0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:tape_device_t:s0 tclass=lnk_file permissive=0 input: syz0 as /devices/virtual/input/input37 input: syz0 as /devices/virtual/input/input38 input: syz0 as /devices/virtual/input/input40 input: syz0 as /devices/virtual/input/input42 input: syz0 as /devices/virtual/input/input46 input: syz0 as /devices/virtual/input/input48 uinput: write device info first uinput: write device info first uinput: write device info first input: syz0 as /devices/virtual/input/input52 uinput: write device info first uinput: write device info first audit: type=1400 audit(1552168853.481:389): avc: denied { create } for pid=9189 comm="syz-executor.2" 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 uinput: write device info first audit: type=1400 audit(1552168853.531:390): avc: denied { create } for pid=9189 comm="syz-executor.2" 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 uinput: write device info first uinput: write device info first uinput: write device info first uinput: write device info first uinput: write device info first uinput: write device info first