Using a slightly modified version of udpspam (see diff below - hopefully not mangled by corporate email servers), where I set the SO_NO_CHECK socket option and can specify a large buffer size, I can reliably get the following WARN trace. I have reproduced this on both ixgbe and i40e drivers using "udpspam-no-check <target-ip> 6000".
It looks to me like this is in the Tx path before we get to the actual NIC drivers, but I may be wrong. [ 1757.644324] ------------[ cut here ]------------ [ 1757.644333] WARNING: CPU: 22 PID: 5537 at net/core/dev.c:2423 skb_warn_bad_offload+0x104/0x111() [ 1757.644340] ixgbe: caps=(0x0000080660314bb3, 0x0000000000000000) len=6092 data_len=6000 gso_size=1528 gso_type=1026 ip_summed=0 [ 1757.644343] Modules linked in: nfnetlink_queue nfnetlink_log nfnetlink vxlan ip6_udp_tunnel udp_tunnel rfcomm xt_CHECKSUM bnep bluetooth rfkill tun fuse ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_mangle iptable_security iptable_raw x86_pkg_temp_thermal coretemp kvm_intel kvm joydev iTCO_wdt ipmi_devintf iTCO_vendor_support irqbypass crct10dif_pclmul ixgbe igb crc32_pclmul ipmi_si ptp pps_core sb_edac lpc_ich crc32c_intel pcspkr edac_core i2c_i801 mfd_core mdio ipmi_msghandler mei_me shpchp tpm_tis ioatdma mei dca wmi tpm binfmt_misc uinput mgag200 i2c_algo_bit drm_kms_helper [ 1757.644443] ttm drm isci libsas firewire_ohci firewire_core i2c_core scsi_transport_sas crc_itu_t [ 1757.644475] CPU: 22 PID: 5537 Comm: udpspam-no-chec Tainted: G W 4.4.0-rc3+ #1 [ 1757.644480] Hardware name: Intel Corporation S2600CO/S2600CO, BIOS SE5C600.86B.02.03.0003.041920141333 04/19/2014 [ 1757.644482] 0000000000000000 00000000c92b03e4 ffff88081907b410 ffffffff8138f918 [ 1757.644488] ffff88081907b458 ffff88081907b448 ffffffff8109c036 ffff8808196e9500 [ 1757.644494] ffff880816f60000 0000000000000402 0000000000000000 ffff88080e8eb2ac [ 1757.644499] Call Trace: [ 1757.644509] [<ffffffff8138f918>] dump_stack+0x44/0x5c [ 1757.644514] [<ffffffff8109c036>] warn_slowpath_common+0x86/0xc0 [ 1757.644518] [<ffffffff8109c0cc>] warn_slowpath_fmt+0x5c/0x80 [ 1757.644523] [<ffffffff813958cc>] ? ___ratelimit+0x8c/0xf0 [ 1757.644539] [<ffffffff8174c77c>] skb_warn_bad_offload+0x104/0x111 [ 1757.644549] [<ffffffff81649d1f>] __skb_gso_segment+0x7f/0xd0 [ 1757.644563] [<ffffffff8164a08f>] validate_xmit_skb.isra.104.part.105+0x11f/0x2a0 [ 1757.644572] [<ffffffff8164a5fb>] validate_xmit_skb_list+0x3b/0x60 [ 1757.644579] [<ffffffff8166e591>] sch_direct_xmit+0xc1/0x1f0 [ 1757.644585] [<ffffffff8164a92b>] __dev_queue_xmit+0x21b/0x510 [ 1757.644589] [<ffffffff8164ac30>] dev_queue_xmit+0x10/0x20 [ 1757.644593] [<ffffffff8168b66f>] ip_finish_output2+0x23f/0x310 [ 1757.644598] [<ffffffff8168c179>] ip_finish_output+0x139/0x1f0 [ 1757.644605] [<ffffffff8167e9d6>] ? nf_hook_slow+0x76/0xd0 [ 1757.644610] [<ffffffff8168d64e>] ip_output+0x6e/0xe0 [ 1757.644615] [<ffffffff8168cd02>] ? __ip_local_out+0x42/0x100 [ 1757.644620] [<ffffffff8168c040>] ? ip_fragment.constprop.49+0x80/0x80 [ 1757.644627] [<ffffffff8168cdf5>] ip_local_out+0x35/0x40 [ 1757.644634] [<ffffffff816d195d>] iptunnel_xmit+0x12d/0x150 [ 1757.644640] [<ffffffffa036326a>] udp_tunnel_xmit_skb+0xea/0x100 [udp_tunnel] [ 1757.644648] [<ffffffffa038a506>] vxlan_xmit_one+0xac6/0x1280 [vxlan] [ 1757.644659] [<ffffffff810ef332>] ? vprintk_emit+0x2f2/0x4f0 [ 1757.644675] [<ffffffff81193772>] ? printk+0x5d/0x74 [ 1757.644681] [<ffffffff8109c045>] ? warn_slowpath_common+0x95/0xc0 [ 1757.644688] [<ffffffffa038bf32>] vxlan_xmit+0x172/0xd44 [vxlan] [ 1757.644694] [<ffffffff816c26a3>] ? inet_gso_segment+0x163/0x360 [ 1757.644711] [<ffffffff8164a43e>] dev_hard_start_xmit+0x22e/0x3b0 [ 1757.644721] [<ffffffff8164ab24>] __dev_queue_xmit+0x414/0x510 [ 1757.644734] [<ffffffff8164ac30>] dev_queue_xmit+0x10/0x20 [ 1757.644747] [<ffffffff8168b66f>] ip_finish_output2+0x23f/0x310 [ 1757.644758] [<ffffffff8168c179>] ip_finish_output+0x139/0x1f0 [ 1757.644763] [<ffffffff8167e9d6>] ? nf_hook_slow+0x76/0xd0 [ 1757.644768] [<ffffffff8168d64e>] ip_output+0x6e/0xe0 [ 1757.644775] [<ffffffff8168cd02>] ? __ip_local_out+0x42/0x100 [ 1757.644780] [<ffffffff8168c040>] ? ip_fragment.constprop.49+0x80/0x80 [ 1757.644785] [<ffffffff8168cdf5>] ip_local_out+0x35/0x40 [ 1757.644793] [<ffffffff8168e0c9>] ip_send_skb+0x19/0x40 [ 1757.644800] [<ffffffff816b41cd>] udp_send_skb+0x16d/0x270 [ 1757.644807] [<ffffffff816b50f8>] udp_sendmsg+0x2c8/0x9a0 [ 1757.644812] [<ffffffff8168b1b0>] ? ip_reply_glue_bits+0x60/0x60 [ 1757.644825] [<ffffffff816c2387>] inet_sendmsg+0x67/0xa0 [ 1757.644838] [<ffffffff8162bf88>] sock_sendmsg+0x38/0x50 [ 1757.644852] [<ffffffff8162c442>] SYSC_sendto+0x102/0x190 [ 1757.644860] [<ffffffff8113842f>] ? __audit_syscall_entry+0xaf/0x100 [ 1757.644867] [<ffffffff81003176>] ? do_audit_syscall_entry+0x66/0x70 [ 1757.644873] [<ffffffff810037ef>] ? syscall_trace_enter_phase1+0x11f/0x140 [ 1757.644879] [<ffffffff81096c6d>] ? syscall_slow_exit_work+0x3f/0x9f [ 1757.644883] [<ffffffff8162cf5e>] SyS_sendto+0xe/0x10 [ 1757.644890] [<ffffffff8175946e>] entry_SYSCALL_64_fastpath+0x12/0x71 [ 1757.644895] ---[ end trace ec9dfd887c59f41f ]--- Here are the udpspam.c diffs from the original that I found at http://oss.sgi.com/archives/netdev/2001-10/txtmtEDzF63p0.txt --- udpspam.c 2015-12-14 16:56:18.287053786 -0800 +++ udpspam-no-check.c 2015-12-14 17:02:21.979047972 -0800 @@ -42,8 +42,8 @@ typedef unsigned long dword; /* Globals */ -#define PAYLOAD_SIZE 4 -static char payload[PAYLOAD_SIZE]; +static int payload_size = 4; +static char *payload; /* Socket functions */ @@ -85,6 +85,8 @@ static int get_udp_socket(){ option = 0; setsockopt(fd,SOL_SOCKET,SO_BROADCAST,(void *)&option,sizeof(option)); + option = 1; + setsockopt(fd,SOL_SOCKET,SO_NO_CHECK,(void *)&option,sizeof(option)); udp.sin_addr.s_addr = htonl(INADDR_ANY); udp.sin_port = htons(0); @@ -123,9 +125,19 @@ int main(int argc,char *argv[]){ exit(-1); socket_connect_address(fd,&remote); - memset(payload,0,PAYLOAD_SIZE); + + if (argc == 3) { + errno = 0; + payload_size = strtol(argv[2], NULL, 0); + if (errno) { + fprintf(stderr, "bad payload size '%s'\n", argv[2]); + exit(1); + } + } + payload = malloc(payload_size); + memset(payload,0,payload_size); while (1) - sendto(fd,payload,PAYLOAD_SIZE,0,(struct sockaddr *)&remote,sizeof(remote)); + sendto(fd,payload,payload_size,0,(struct sockaddr *)&remote,sizeof(remote)); exit(0); } ====================================================================== Mr. Shannon Nelson Network Division, Intel Corp. shannon.nel...@intel.com I don't speak for Intel (503) 712-7659 Parents can't afford to be squeamish -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
