=============================== [ 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 udevd/7117: #0: (&sig->cred_guard_mutex){+.+.+.}, at: [] prepare_bprm_creds+0x55/0x120 fs/exec.c:1225 #1: (&mm->mmap_sem){++++++}, at: [] __might_fault+0xe7/0x1d0 mm/memory.c:3866 #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: 7117 Comm: udevd Not tainted 4.4.174+ #4 0000000000000000 fcff85f47d21a973 ffff8801db607940 ffffffff81aad1a1 ffff8801d3eb3180 0000000000000000 0000000000000001 00000000000005b9 ffff8800b55cc740 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 input: syz1 as /devices/virtual/input/input28 [] 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] [] ? lock_acquire+0x19f/0x450 kernel/locking/lockdep.c:3595 [] __might_fault mm/memory.c:3867 [inline] [] __might_fault+0x14d/0x1d0 mm/memory.c:3852 [] get_user_arg_ptr.isra.0+0x32/0xa0 fs/exec.c:447 [] copy_strings.isra.0+0xeb/0x7c0 fs/exec.c:501 [] do_execveat_common.isra.0+0xea5/0x1e90 fs/exec.c:1633 [] do_execve fs/exec.c:1683 [inline] [] SYSC_execve fs/exec.c:1764 [inline] [] SyS_execve+0x42/0x50 fs/exec.c:1759 [] stub_execve+0x5/0x5 arch/x86/entry/entry_64.S:440 input: syz1 as /devices/virtual/input/input29 input: syz1 as /devices/virtual/input/input30 input: syz1 as /devices/virtual/input/input31 input: syz1 as /devices/virtual/input/input32 audit: type=1400 audit(1552218122.028:24): avc: denied { getattr } for pid=7204 comm="syz-executor.2" path="socket:[24605]" dev="sockfs" ino=24605 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=1 input: syz1 as /devices/virtual/input/input33 input: syz1 as /devices/virtual/input/input34 input: syz1 as /devices/virtual/input/input35 input: syz1 as /devices/virtual/input/input36 input: syz1 as /devices/virtual/input/input37 audit: type=1400 audit(1552218123.608:25): avc: denied { setattr } for pid=7284 comm="syz-executor.0" name="NETLINK" dev="sockfs" ino=24121 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1 input: syz1 as /devices/virtual/input/input38 input: syz1 as /devices/virtual/input/input39 input: syz1 as /devices/virtual/input/input40 input: syz1 as /devices/virtual/input/input43 uinput: write device info first uinput: write device info first input: syz1 as /devices/virtual/input/input47 uinput: write device info first input: syz1 as /devices/virtual/input/input49 input: syz1 as /devices/virtual/input/input50 uinput: write device info first uinput: write device info first input: syz1 as /devices/virtual/input/input53 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 uinput: write device info first uinput: write device info first uinput: write device info first input: syz1 as /devices/virtual/input/input69 uinput: write device info first input: syz1 as /devices/virtual/input/input70 input: syz1 as /devices/virtual/input/input72 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