Hi, First let me say thank you. I'm at my wits end with this one, 1 week in with very little understanding of it. Report [23931.226534] general protection fault, probably for non-canonical address 0x567a6d51644d6bd5: 0000 [#1] SMP NOPTI [23931.226681] CPU: 7 PID: 0 Comm: swapper/7 Tainted: G O 5.7.5+ #2 [23931.226820] Hardware name: Supermicro Super Server/X11SSL-F, BIOS 1.0b 12/29/2015 [23931.226988] RIP: 0010:get_unique_tuple+0xc7/0x750 [nf_nat] [23931.227156] Code: 75 22 e9 c3 00 00 00 4d 8b b6 98 00 00 00 4d 85 f6 0f 84 b3 00 00 00 49 81 ee 98 00 00 00 0f 84 a6 00 00 00 41 0f b6 44 24 26 <41> 38 46 46 75 d7 49 8b 4e 20 49 8b 46 28 49 33 0c 24 49 33 44 24 [23931.227516] RSP: 0018:ffffc90000224b10 EFLAGS: 00010202 [23931.227707] RAX: 0000000000000006 RBX: 0000000000000000 RCX: ffffc9000165a000 [23931.227908] RDX: ffffffff820f4300 RSI: 00000000e7e71126 RDI: 0000000069808c21 [23931.228145] RBP: ffffc90000224b80 R08: 0000000000000000 R09: 0000000000000000 [23931.228356] R10: 00000000000001ff R11: 0000000000000000 R12: ffffc90000224b90 [23931.228572] R13: ffffc90000224bb8 R14: 567a6d51644d6bd5 R15: ffffc90000224c38 [23931.228794] FS: 0000000000000000(0000) GS:ffff888467bc0000(0000) knlGS:0000000000000000 [23931.229026] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [23931.229262] CR2: 00007ffc1ac6ef0a CR3: 000000000200a002 CR4: 00000000003606e0 [23931.229508] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [23931.229758] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [23931.230037] Call Trace: [23931.230290] <IRQ> [23931.230546] ? check_preempt_curr+0x7a/0x90 [23931.230807] ? hash_ipport4_test+0x12f/0x150 [ip_set_hash_ipport] [23931.231079] nf_nat_setup_info+0x8a/0x260 [nf_nat] [23931.231353] ? dsthash_find+0x133/0x140 [xt_hashlimit] [23931.231632] xt_sdnat_target_v1+0xc6/0xcd [xt_SDNAT] [23931.231918] ? ipt_do_table+0x30a/0x6f0 [ip_tables] [23931.232263] ? ipt_do_table+0x3ca/0x6f0 [ip_tables] [23931.232553] ? nf_nat_inet_fn+0xea/0x210 [nf_nat] [23931.232847] ? nf_nat_ipv4_in+0x25/0x60 [nf_nat] [23931.233267] ? nf_hook_slow+0x44/0xc0 [23931.233566] ? ip_rcv+0x91/0xd0 [23931.233866] ? ip_rcv_finish_core.isra.18+0x400/0x400 [23931.234173] ? __netif_receive_skb_one_core+0x85/0xa0 [23931.234484] ? process_backlog+0xaa/0x160 [23931.234823] ? net_rx_action+0x149/0x3c0 [23931.235150] ? __do_softirq+0xdf/0x2e5 [23931.235461] ? handle_irq_event_percpu+0x6d/0x80 [23931.235872] ? irq_exit+0xa3/0xb0 [23931.236264] ? do_IRQ+0x56/0xe0 [23931.236681] ? common_interrupt+0xf/0xf [23931.236993] </IRQ> [23931.237303] ? cpuidle_enter_state+0xbe/0x3f0 [23931.237617] ? cpuidle_enter+0x29/0x40 [23931.237930] ? do_idle+0x22b/0x260 [23931.238282] ? cpu_startup_entry+0x19/0x20 [23931.238703] ? start_secondary+0x169/0x1c0 [23931.239103] ? secondary_startup_64+0xa4/0xb0 I am aware that this kernel is tainted, it's tainted by xt_SDNAT (https://github.com/splitice/xt_SDNAT). Despite my best efforts I have not yet been able to make this happen in a testing environment (with or without tainting). get_unique_tuple+0xc7/0x750 corresponds to same_src in: /* Only called for SRC manip */ static int find_appropriate_src(struct net *net, const struct nf_conntrack_zone *zone, const struct nf_conntrack_tuple *tuple, struct nf_conntrack_tuple *result, const struct nf_nat_range2 *range) { unsigned int h = hash_by_src(net, tuple); const struct nf_conn *ct; hlist_for_each_entry_rcu(ct, &nf_nat_bysource[h], nat_bysource) { if (same_src(ct, tuple) && net_eq(net, nf_ct_net(ct)) && nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL)) { /* Copy source part from reply tuple. */ nf_ct_invert_tuple(result, &ct->tuplehash[IP_CT_DIR_REPLY].tuple); result->dst = tuple->dst; if (in_range(result, range)) return 1; } } return 0; } Does anyone have any ideas about what this could be? Regards, Mathew
