Re: [dpdk-dev] URGENT please help. Issue on ixgbe_tx_free_bufs version 2.0.0

[Bruce Richardson <bruce.richardson@intel.com>]

On Tue, Nov 10, 2015 at 01:35:21AM -0300, Ariel Rodriguez wrote:
> Dear dpdk experts.
> 
> Im having a recurrent segmentation fault under the
> function ixgbe_tx_free_bufs (ixgbe_rxtx.c:150) (i enable -g3 -O0).
> 
> Surfing the core dump i find out this:
> 
> txep = &(txq->sw_ring[txq->tx_next_dd - (txq->tx_rs_thresh - 1)]);
> 
> txq->tx_next_dd = 31
> txq->txq->tx_rs_thresh=32
> 
> Obviosly txep points out to the first element but
> 
> *(txep).mbuf == INVALID MBUF ADDRESS
> 
> The same applies to
> 
> *(txep+1).mbuf ; *(txep +2).mbuf;*(txep+3).mbuf
> 
> from *(txep+4) .mbuf to *(txep+31).mbuf seems to be valid because im able
> to derefence the mbuf's
> 
> 
> Note:
> 
> I disable CONFIG_RTE_IXGBE_INC_VECTOR because i gets similiar behavior , I
> thought the problem would disappear disabling that feature.
> 
> 
> the program always  runs well up to 4 or 5 hours and then crash ... always
> in the same line.
> 
> this is the backtrace of the program:
> 
> #0  0x0000000000677a64 in rte_atomic16_read (v=0x47dc14c18b14) at
> /opt/dpdk-2.0.0/x86_64-native-linuxapp-gcc/include/generic/rte_atomic.h:151
> #1  0x0000000000677c1d in rte_mbuf_refcnt_read (m=0x47dc14c18b00) at
> /opt/dpdk-2.0.0/x86_64-native-linuxapp-gcc/include/rte_mbuf.h:411
> #2  0x000000000067a13c in __rte_pktmbuf_prefree_seg (m=0x47dc14c18b00) at
> /opt/dpdk-2.0.0/x86_64-native-linuxapp-gcc/include/rte_mbuf.h:778
> #3  rte_pktmbuf_free_seg (m=0x47dc14c18b00) at
> /opt/dpdk-2.0.0/x86_64-native-linuxapp-gcc/include/rte_mbuf.h:810
> #4  ixgbe_tx_free_bufs (txq=0x7ffb40ae52c0) at
> /opt/dpdk-2.0.0/lib/librte_pmd_ixgbe/ixgbe_rxtx.c:150
> #5  tx_xmit_pkts (tx_queue=0x7ffb40ae52c0, tx_pkts=0x64534770 <app+290608>,
> nb_pkts=32) at /opt/dpdk-2.0.0/lib/librte_pmd_ixgbe/ixgbe_rxtx.c:256
> #6  0x000000000067c6f3 in ixgbe_xmit_pkts_simple (tx_queue=0x7ffb40ae52c0,
> tx_pkts=0x64534570 <app+290096>, nb_pkts=80) at
> /opt/dpdk-2.0.0/lib/librte_pmd_ixgbe/ixgbe_rxtx.c:343
> #7  0x00000000004ec93d in rte_eth_tx_burst (port_id=1 '\001', queue_id=0,
> tx_pkts=0x64534570 <app+290096>, nb_pkts=144) at
> /opt/dpdk-2.0.0/x86_64-native-linuxapp-gcc/include/rte_ethdev.h:2572
>
Hi,

I'd like a bit more information to help debug your problem:
* what application are you running when you see this crash? If it's an app of your
own making, can you reproduce the crash using one of the standard DPDK apps, or
example apps, e.g. testpmd, l2fwd, etc.

* Can you also try to verify if the crash occurs with the latest DPDK code available
in git from dpdk.org?

Regards,
/Bruce