From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id B83B4A034E for ; Sun, 7 Jun 2020 15:36:04 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 0299A1BFF0; Sun, 7 Jun 2020 15:36:04 +0200 (CEST) Received: from wh10.alp1.flow.ch (wh10.alp1.flow.ch [185.119.84.194]) by dpdk.org (Postfix) with ESMTP id DFDA41BEB4 for ; Sun, 7 Jun 2020 15:36:02 +0200 (CEST) Received: from [::1] (port=49560 helo=wh10.alp1.flow.ch) by wh10.alp1.flow.ch with esmtpa (Exim 4.92) (envelope-from ) id 1jhvSz-00FIQS-Dw; Sun, 07 Jun 2020 15:36:01 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Date: Sun, 07 Jun 2020 15:36:01 +0200 From: Alex Kiselev To: Cliff Burdick Cc: Stephen Hemminger , users In-Reply-To: References: <504fcb6e5a12a03035e7b55507e7c279@therouter.net> <20200601091729.03ea9e50@hermes.lan> <7DA537F2-9887-4B0A-9249-064736E8A9AD@therouter.net> Message-ID: <5e91c3aa80e354241b03b908f5529d6b@therouter.net> X-Sender: alex@therouter.net User-Agent: Roundcube Webmail/1.3.8 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - wh10.alp1.flow.ch X-AntiAbuse: Original Domain - dpdk.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - therouter.net X-Get-Message-Sender-Via: wh10.alp1.flow.ch: authenticated_id: alex@therouter.net X-Authenticated-Sender: wh10.alp1.flow.ch: alex@therouter.net X-Source: X-Source-Args: X-Source-Dir: Subject: Re: [dpdk-users] segmention fault while accessing mbuf X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: users-bounces@dpdk.org Sender: "users" On 2020-06-07 15:16, Cliff Burdick wrote: > That shouldn't matter. The mbuf size is allocated when you create the > mempool, and data_len/pkt_len are just to specify the size of the > total packet and each segment. The underlying storage size is still > the same. It does matter. I've done some tests and after sending a few mbufs with data_len/pkt_len bigger than the size of mbuf's underlying buffer the app stops sending/receiving packets. The PMD apparently goes beyong the mbuf's buffer, that's why I sill think that my question about the impact of using incorrect data_len/pkt is valid. > > Have you checked to see if it's potentially a hugepage issue? Please, explain. The app had been working two monghts before the crush and the load was 3-4 gbit/s, so no, I don't think that something is wrong with hugepages on that machine. > > On Sun, Jun 7, 2020, 02:59 Alex Kiselev wrote: > >> On 2020-06-07 04:41, Cliff Burdick wrote: >>> I can't tell from your code, but you assigned nb_rx to the number >> of >>> packets received, but then used vec_size, which might be larger. >> Does >>> this happen if you use nb_rx in your loops? >> >> No, this doesn't happen. >> I just skip the part of the code that translates nb_rx to vec_size, >> since that code is double checked. >> >> My actual question now is about possible impact of using >> incorrect values of mbuf's pkt_len and data_len fields. >> >>> >>> On Sat, Jun 6, 2020 at 5:59 AM Alex Kiselev >>> wrote: >>> >>>>> 1 июня 2020 г., в 19:17, Stephen Hemminger >>>> написал(а): >>>>> >>>>> On Mon, 01 Jun 2020 15:24:25 +0200 >>>>> Alex Kiselev wrote: >>>>> >>>>>> Hello, >>>>>> >>>>>> I've got a segmentation fault error in my data plane path. >>>>>> I am pretty sure the code where the segfault happened is ok, >>>>>> so my guess is that I somehow received a corrupted mbuf. >>>>>> How could I troubleshoot this? Is there any way? >>>>>> Is it possible that other threads of the application >>>>>> corrupted that mbuf? >>>>>> >>>>>> I would really appriciate any advice. >>>>>> Thanks. >>>>>> >>>>>> DPDK 18.11.3 >>>>>> NIC: 82599ES >>>>>> >>>>>> Code: >>>>>> >>>>>> nb_rx = rte_eth_rx_burst(port_id, queue_id, pkts_burst, >>>>>> MAX_PKT_BURST); >>>>>> >>>>>> ... >>>>>> >>>>>> for (i=0; i < vec_size; i++) { >>>>>> rte_prefetch0(rte_pktmbuf_mtod(m_v[i], void *)); >>>>>> >>>>>> for (i=0; i < vec_size; i++) { >>>>>> m = m_v[i]; >>>>>> eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *); >>>>>> eth_type = rte_be_to_cpu_16(eth_hdr->ether_type); >>>> <--- >>>>>> Segmentation fault >>>>>> ... >>>>>> >>>>>> #0 rte_arch_bswap16 (_x=>>> memory >>>>>> at address 0x4d80000000053010>) >>>>> >>>>> Build with as many of the debug options turned on in the DPDK >>>> config, >>>>> and build with EXTRA_CFLAGS of -g. >>>> >>>> Could using an incorrect (a very big one) value of mbuf pkt_len >> and >>>> data_len while transmitting cause mbuf corruption and following >>>> segmentation fault on rx?