============================= WARNING: suspicious RCU usage 4.14.156-syzkaller #0 Not tainted ----------------------------- net/ipv6/ip6_fib.c:1590 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 4 locks held by swapper/0/0: #0: (((&net->ipv6.ip6_fib_timer))){+.-.}, at: [<0000000038159edc>] lockdep_copy_map include/linux/lockdep.h:174 [inline] #0: (((&net->ipv6.ip6_fib_timer))){+.-.}, at: [<0000000038159edc>] call_timer_fn+0xc6/0x6a0 kernel/time/timer.c:1269 #1: (&(&net->ipv6.fib6_gc_lock)->rlock){+.-.}, at: [<0000000049cc45f1>] spin_lock_bh include/linux/spinlock.h:322 [inline] #1: (&(&net->ipv6.fib6_gc_lock)->rlock){+.-.}, at: [<0000000049cc45f1>] fib6_run_gc+0x93/0x2a0 net/ipv6/ip6_fib.c:1938 #2: (rcu_read_lock){....}, at: [<000000001cc9e33a>] __fib6_clean_all+0x0/0x230 net/ipv6/ip6_fib.c:1823 #3: (&tb->tb6_lock){++--}, at: [<0000000014b50bbf>] __fib6_clean_all+0xde/0x230 net/ipv6/ip6_fib.c:1837 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.156-syzkaller #0 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xe5/0x154 lib/dump_stack.c:58 fib6_del+0x88d/0xbb0 net/ipv6/ip6_fib.c:1590 fib6_clean_node+0x270/0x440 net/ipv6/ip6_fib.c:1777 fib6_walk_continue+0x3a5/0x5f0 net/ipv6/ip6_fib.c:1703 fib6_walk+0x8d/0xe0 net/ipv6/ip6_fib.c:1748 fib6_clean_tree+0xd4/0x110 net/ipv6/ip6_fib.c:1822 __fib6_clean_all+0xf5/0x230 net/ipv6/ip6_fib.c:1838 fib6_clean_all net/ipv6/ip6_fib.c:1849 [inline] fib6_run_gc+0x104/0x2a0 net/ipv6/ip6_fib.c:1947 call_timer_fn+0x15b/0x6a0 kernel/time/timer.c:1279 expire_timers+0x227/0x4c0 kernel/time/timer.c:1318 __run_timers kernel/time/timer.c:1636 [inline] run_timer_softirq+0x1eb/0x5d0 kernel/time/timer.c:1649 __do_softirq+0x234/0x9ec kernel/softirq.c:288 invoke_softirq kernel/softirq.c:368 [inline] irq_exit+0x114/0x150 kernel/softirq.c:409 exiting_irq arch/x86/include/asm/apic.h:648 [inline] smp_apic_timer_interrupt+0x1a7/0x650 arch/x86/kernel/apic/apic.c:1102 apic_timer_interrupt+0x8c/0xa0 arch/x86/entry/entry_64.S:792 RIP: 0010:native_safe_halt+0x13/0x20 arch/x86/include/asm/irqflags.h:61 RSP: 0018:ffffffffa6207d48 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10 RAX: 0000000000000000 RBX: ffffffffa66318a8 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffffa623156c RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffffa6230d40 R15: dffffc0000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0x61/0x3b0 arch/x86/kernel/process.c:566 cpuidle_idle_call kernel/sched/idle.c:159 [inline] do_idle+0x2e6/0x390 kernel/sched/idle.c:268 cpu_startup_entry+0xc6/0xd0 kernel/sched/idle.c:374 start_kernel+0x858/0x890 init/main.c:733 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240 selinux_nlmsg_perm: 5 callbacks suppressed SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=14045 comm=syz-executor.2 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=14045 comm=syz-executor.2 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=14045 comm=syz-executor.2 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=14045 comm=syz-executor.2 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=14045 comm=syz-executor.2 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=14045 comm=syz-executor.2 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=14045 comm=syz-executor.2 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=14045 comm=syz-executor.2 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=14045 comm=syz-executor.2 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=14045 comm=syz-executor.2