audit: type=1400 audit(2000000626.212:3394): avc:  denied  { read } for  pid=1207 comm="syz-executor.0" 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
===============================
[ 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
5 locks held by syz-executor.5/2114:
 #0:  (rcu_read_lock){......}, at: [<ffffffff819f114c>] INIT_LIST_HEAD include/linux/list.h:28 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff819f114c>] avc_compute_av+0xac/0x610 security/selinux/avc.c:973
 #1:  (((&net->ipv6.ip6_fib_timer))){+.-...}, at: [<ffffffff812624fe>] lockdep_copy_map include/linux/lockdep.h:165 [inline]
 #1:  (((&net->ipv6.ip6_fib_timer))){+.-...}, at: [<ffffffff812624fe>] call_timer_fn+0xde/0x6d0 kernel/time/timer.c:1309
 #2:  (&(&net->ipv6.fib6_gc_lock)->rlock){+.-...}, at: [<ffffffff826ef1e2>] spin_lock_bh include/linux/spinlock.h:307 [inline]
 #2:  (&(&net->ipv6.fib6_gc_lock)->rlock){+.-...}, at: [<ffffffff826ef1e2>] fib6_run_gc+0xa2/0x2e0 net/ipv6/ip6_fib.c:1816
 #3:  (rcu_read_lock){......}, at: [<ffffffff826e69f0>] __fib6_clean_all+0x0/0x230 net/ipv6/ip6_fib.c:1703
 #4:  (&tb->tb6_lock){++--..}, at: [<ffffffff826e6ad3>] __fib6_clean_all+0xe3/0x230 net/ipv6/ip6_fib.c:1717

stack backtrace:
CPU: 0 PID: 2114 Comm: syz-executor.5 Not tainted 4.9.155+ #27
 ffff8801db607890 ffffffff81b47871 ffff8801791cdc00 0000000000000000
 0000000000000002 00000000000005be ffff8801d66b17c0 ffff8801db6078c0
 ffffffff813fed99 ffff8801db607ae0 dffffc0000000000 00000000ffffffff
Call Trace:
 <IRQ> [ 1244.061837]  [<ffffffff81b47871>] __dump_stack lib/dump_stack.c:15 [inline]
 <IRQ> [ 1244.061837]  [<ffffffff81b47871>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<ffffffff813fed99>] lockdep_rcu_suspicious.cold+0x10a/0x149 kernel/locking/lockdep.c:4455
 [<ffffffff826ee93f>] fib6_del+0x81f/0xb20 net/ipv6/ip6_fib.c:1470
 [<ffffffff826eeedc>] fib6_clean_node+0x29c/0x4d0 net/ipv6/ip6_fib.c:1657
 [<ffffffff826e62c0>] fib6_walk_continue+0x3e0/0x630 net/ipv6/ip6_fib.c:1583
 [<ffffffff826e687d>] fib6_walk+0x9d/0xf0 net/ipv6/ip6_fib.c:1628
 [<ffffffff826e69b7>] fib6_clean_tree+0xe7/0x120 net/ipv6/ip6_fib.c:1702
 [<ffffffff826e6aeb>] __fib6_clean_all+0xfb/0x230 net/ipv6/ip6_fib.c:1718
 [<ffffffff826ef264>] fib6_clean_all net/ipv6/ip6_fib.c:1729 [inline]
 [<ffffffff826ef264>] fib6_run_gc+0x124/0x2e0 net/ipv6/ip6_fib.c:1826
 [<ffffffff826ef43d>] fib6_gc_timer_cb+0x1d/0x30 net/ipv6/ip6_fib.c:1841
 [<ffffffff81262587>] call_timer_fn+0x167/0x6d0 kernel/time/timer.c:1319
 [<ffffffff81262d4b>] expire_timers+0x25b/0x5c0 kernel/time/timer.c:1359
 [<ffffffff812632af>] __run_timers kernel/time/timer.c:1674 [inline]
 [<ffffffff812632af>] run_timer_softirq+0x1ff/0x620 kernel/time/timer.c:1687
 [<ffffffff8281be7d>] __do_softirq+0x22d/0x964 kernel/softirq.c:288
 [<ffffffff810eecd9>] invoke_softirq kernel/softirq.c:368 [inline]
 [<ffffffff810eecd9>] irq_exit+0x119/0x160 kernel/softirq.c:409
 [<ffffffff8281a9be>] exiting_irq arch/x86/include/asm/apic.h:669 [inline]
 [<ffffffff8281a9be>] smp_apic_timer_interrupt+0x7e/0xb0 arch/x86/kernel/apic/apic.c:962
 [<ffffffff8281822d>] apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> [ 1244.340654]  [<ffffffff828161bf>] ? arch_local_irq_restore arch/x86/include/asm/paravirt.h:768 [inline]
 <EOI> [ 1244.340654]  [<ffffffff828161bf>] ? __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:162 [inline]
 <EOI> [ 1244.340654]  [<ffffffff828161bf>] ? _raw_spin_unlock_irqrestore+0x5f/0x70 kernel/locking/spinlock.c:191
 [<ffffffff819efe6a>] spin_unlock_irqrestore include/linux/spinlock.h:362 [inline]
 [<ffffffff819efe6a>] avc_reclaim_node security/selinux/avc.c:541 [inline]
 [<ffffffff819efe6a>] avc_alloc_node security/selinux/avc.c:559 [inline]
 [<ffffffff819efe6a>] avc_alloc_node+0x29a/0x3c0 security/selinux/avc.c:547
 [<ffffffff819f1222>] avc_insert security/selinux/avc.c:670 [inline]
 [<ffffffff819f1222>] avc_compute_av+0x182/0x610 security/selinux/avc.c:976
 [<ffffffff819f2f65>] avc_has_perm_noaudit security/selinux/avc.c:1112 [inline]
 [<ffffffff819f2f65>] avc_has_perm+0x355/0x3a0 security/selinux/avc.c:1146
 [<ffffffff819fa70f>] sock_has_perm+0x28f/0x3e0 security/selinux/hooks.c:4255
 [<ffffffff819fa93f>] selinux_socket_getsockopt+0x3f/0x50 security/selinux/hooks.c:4535
 [<ffffffff819eda43>] security_socket_getsockopt+0x83/0xc0 security/security.c:1311
 [<ffffffff822a867a>] SYSC_getsockopt net/socket.c:1806 [inline]
 [<ffffffff822a867a>] SyS_getsockopt+0xca/0x220 net/socket.c:1798
 [<ffffffff810056bd>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285
 [<ffffffff82816a93>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb