4.18.20 works OK, but unfortunately 4.18 series is EOL. I have Ryzen 1600X, 32 GB RAM, Fedora 28, gcc-8.2.1-5, nosmt=force, igb module for Intel I211, using XFS filesystems only.
To reproduce, I only do this: connect to VPN using a tunnel (e.g. tun0), start downloading a file with qbittorrent (allow port for incoming TCP connections in qbittorrent and iptables) and wait a couple of minutes. I am also using ipset and connlimit modules. I reproduced this bug three times. With 4.18 I use fq+htb and with 4.19 I use CAKE for traffic control. Only this message in kernel log: [ 363.935074] TCP: request_sock_TCP: Possible SYN flooding on port 19044. Dropping request. Check SNMP counters. I get this message with both 4.18.20 and 4.19.4. RIP: 0010:rb_insert_color+0x64 Call Trace: nf_conntrack_count [nf_conncount] ip_set_test [ip_set] connlimit_mt [xt_connlimit] set_match_v4 [xt_set] ipt_do_table [ip_tables] ip_route_input_noref nf_hook_slow ip_local_deliver inet_add_protocol ip_rcv ip_rcv_finish_core __netif_receive_skb_one_core netif_receive_skb_internal tun_rx_batched tun_get_user __local_bh_enable_ip tun_get_user tun_chr_write_iter __vfs_write vfs_write ksys_write do_syscall_64 trace_hardirqs_off_thunk entry_SYSCALL_64_after_hwframe ... Kernel panic - not syncing: Fatal exception in interrupt -- Do what you love because life is too short for anything else. https://samifar.in/
