[dpdk-dev] Segmentation fault in ixgbe_rxtx_vec.c:444 with 1.8.0
Bruce Richardson
bruce.richardson at intel.com
Wed Jan 21 14:49:21 CET 2015
On Tue, Jan 20, 2015 at 11:39:03AM +0100, Martin Weiser wrote:
> Hi again,
>
> I did some further testing and it seems like this issue is linked to
> jumbo frames. I think a similar issue has already been reported by
> Prashant Upadhyaya with the subject 'Packet Rx issue with DPDK1.8'.
> In our application we use the following rxmode port configuration:
>
> .mq_mode = ETH_MQ_RX_RSS,
> .split_hdr_size = 0,
> .header_split = 0,
> .hw_ip_checksum = 1,
> .hw_vlan_filter = 0,
> .jumbo_frame = 1,
> .hw_strip_crc = 1,
> .max_rx_pkt_len = 9000,
>
> and the mbuf size is calculated like the following:
>
> (2048 + sizeof(struct rte_mbuf) + RTE_PKTMBUF_HEADROOM)
>
> This works fine with DPDK 1.7 and jumbo frames are split into buffer
> chains and can be forwarded on another port without a problem.
> With DPDK 1.8 and the default configuration (CONFIG_RTE_IXGBE_INC_VECTOR
> enabled) the application sometimes crashes like described in my first
> mail and sometimes packet receiving stops with subsequently arriving
> packets counted as rx errors. When CONFIG_RTE_IXGBE_INC_VECTOR is
> disabled the packet processing also comes to a halt as soon as jumbo
> frames arrive with a the slightly different effect that now
> rte_eth_tx_burst refuses to send any previously received packets.
>
> Is there anything special to consider regarding jumbo frames when moving
> from DPDK 1.7 to 1.8 that we might have missed?
>
> Martin
>
>
>
> On 19.01.15 11:26, Martin Weiser wrote:
> > Hi everybody,
> >
> > we quite recently updated one of our applications to DPDK 1.8.0 and are
> > now seeing a segmentation fault in ixgbe_rxtx_vec.c:444 after a few minutes.
> > I just did some quick debugging and I only have a very limited
> > understanding of the code in question but it seems that the 'continue'
> > in line 445 without increasing 'buf_idx' might cause the problem. In one
> > debugging session when the crash occurred the value of 'buf_idx' was 2
> > and the value of 'pkt_idx' was 8965.
> > Any help with this issue would be greatly appreciated. If you need any
> > further information just let me know.
> >
> > Martin
> >
> >
>
Hi Martin, Prashant,
I've managed to reproduce the issue here and had a look at it. Could you
both perhaps try the proposed change below and see if it fixes the problem for
you and gives you a working system? If so, I'll submit this as a patch fix
officially - or go back to the drawing board, if not. :-)
diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
index b54cb19..dfaccee 100644
--- a/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
+++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx_vec.c
@@ -402,10 +402,10 @@ reassemble_packets(struct igb_rx_queue *rxq, struct rte_mbuf **rx_bufs,
struct rte_mbuf *pkts[RTE_IXGBE_VPMD_RX_BURST]; /*finished pkts*/
struct rte_mbuf *start = rxq->pkt_first_seg;
struct rte_mbuf *end = rxq->pkt_last_seg;
- unsigned pkt_idx = 0, buf_idx = 0;
+ unsigned pkt_idx, buf_idx;
- while (buf_idx < nb_bufs) {
+ for (buf_idx = 0, pkt_idx = 0; buf_idx < nb_bufs; buf_idx++) {
if (end != NULL) {
/* processing a split packet */
end->next = rx_bufs[buf_idx];
@@ -448,7 +448,6 @@ reassemble_packets(struct igb_rx_queue *rxq, struct rte_mbuf **rx_bufs,
rx_bufs[buf_idx]->data_len += rxq->crc_len;
rx_bufs[buf_idx]->pkt_len += rxq->crc_len;
}
- buf_idx++;
}
/* save the partial packet for next time */
Regards,
/Bruce
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