ip_tables: iptables: counters copy to user failed while replacing table ============================= WARNING: suspicious RCU usage 4.14.281-syzkaller #0 Not tainted ----------------------------- net/netfilter/nf_queue.c:244 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by syz-fuzzer/7986: #0: (rcu_callback){....}, at: [] __rcu_reclaim kernel/rcu/rcu.h:185 [inline] #0: (rcu_callback){....}, at: [] rcu_do_batch kernel/rcu/tree.c:2699 [inline] #0: (rcu_callback){....}, at: [] invoke_rcu_callbacks kernel/rcu/tree.c:2962 [inline] #0: (rcu_callback){....}, at: [] __rcu_process_callbacks kernel/rcu/tree.c:2929 [inline] #0: (rcu_callback){....}, at: [] rcu_process_callbacks+0x84e/0x1180 kernel/rcu/tree.c:2946 #1: (&(&inst->lock)->rlock){+.-.}, at: [] spin_lock_bh include/linux/spinlock.h:322 [inline] #1: (&(&inst->lock)->rlock){+.-.}, at: [] nfqnl_flush+0x2f/0x2a0 net/netfilter/nfnetlink_queue.c:232 stack backtrace: CPU: 0 PID: 7986 Comm: syz-fuzzer Not tainted 4.14.281-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 nf_reinject+0x56e/0x700 net/netfilter/nf_queue.c:244 nfqnl_flush+0x1ab/0x2a0 net/netfilter/nfnetlink_queue.c:237 instance_destroy_rcu+0x19/0x30 net/netfilter/nfnetlink_queue.c:171 __rcu_reclaim kernel/rcu/rcu.h:195 [inline] rcu_do_batch kernel/rcu/tree.c:2699 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2962 [inline] __rcu_process_callbacks kernel/rcu/tree.c:2929 [inline] rcu_process_callbacks+0x780/0x1180 kernel/rcu/tree.c:2946 __do_softirq+0x24d/0x9ff kernel/softirq.c:288 invoke_softirq kernel/softirq.c:368 [inline] irq_exit+0x193/0x240 kernel/softirq.c:409 exiting_irq arch/x86/include/asm/apic.h:638 [inline] smp_apic_timer_interrupt+0x141/0x5e0 arch/x86/kernel/apic/apic.c:1106 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x50/0x80 kernel/locking/spinlock.c:200 RSP: 0018:ffff8880a2e07a98 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10 RAX: 1ffffffff11e1313 RBX: ffff8880b3554480 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880b3554d04 RBP: ffff8880ba434380 R08: ffffffff8b9caa48 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ba434380 R13: ffff8880b3dfe200 R14: 0000000000000000 R15: ffff8880ba434cd0 finish_lock_switch kernel/sched/sched.h:1346 [inline] finish_task_switch+0x178/0x610 kernel/sched/core.c:2678 context_switch kernel/sched/core.c:2814 [inline] __schedule+0x893/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 schedule_hrtimeout_range_clock+0x156/0x320 kernel/time/hrtimer.c:1719 ep_poll+0x85e/0xa50 fs/eventpoll.c:1827 SYSC_epoll_wait fs/eventpoll.c:2195 [inline] SyS_epoll_wait+0x150/0x1a0 fs/eventpoll.c:2160 SYSC_epoll_pwait fs/eventpoll.c:2226 [inline] SyS_epoll_pwait+0x1e9/0x230 fs/eventpoll.c:2206 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x466ae0 RSP: 002b:000000c0000977e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000119 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000466ae0 RDX: 0000000000000080 RSI: 000000c000097840 RDI: 0000000000000003 RBP: 000000c000097e40 R08: 0000000000000000 R09: 00000022e2c0aff8 R10: 0000000000000207 R11: 0000000000000246 R12: 000000c000097870 R13: 0000000000000000 R14: 000000c0000824e0 R15: 0000000000000000 netlink: 12 bytes leftover after parsing attributes in process `syz-executor.1'. ip_tables: iptables: counters copy to user failed while replacing table netlink: 12 bytes leftover after parsing attributes in process `syz-executor.1'. ip_tables: iptables: counters copy to user failed while replacing table EXT4-fs (loop2): mounted filesystem without journal. Opts: ,errors=continue netlink: 12 bytes leftover after parsing attributes in process `syz-executor.1'. capability: warning: `syz-executor.2' uses 32-bit capabilities (legacy support in use) ip_tables: iptables: counters copy to user failed while replacing table bridge0: port 2(bridge_slave_1) entered disabled state bridge0: port 1(bridge_slave_0) entered disabled state unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 audit: type=1800 audit(1654309612.020:10): pid=10817 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.3" name="bus" dev="sda1" ino=14101 res=0 EXT4-fs (loop2): mounted filesystem without journal. Opts: ,errors=continue