Re: [dpdk-dev] [Bug 248] Bonding PMD: Invalid array dimension in TX burst for 802.3ad mode with fast queue leads to SEGFAULT

["Przemysław Ołtarzewski" <p.oltarzewski@gmail.com>]

Hello David,

I can merge these fixes and run our system using patched DPDK version. Then
report back any problems / improvements I observe. I can also walk through
source code changes and check for anything questionable.

Unfortunately I lack deep enough understanding of DPDK source code to test
these fixes comprehensively and I have been short on time recently as well,
so that's the best I can do right now.

Best Regards,
Przemysław Ołtarzewski

On Tue, Apr 9, 2019 at 4:51 PM David Marchand <david.marchand@redhat.com>
wrote:

>
>
> On Tue, Apr 9, 2019 at 4:45 PM <bugzilla@dpdk.org> wrote:
>
>> https://bugs.dpdk.org/show_bug.cgi?id=248
>>
>>             Bug ID: 248
>>            Summary: Bonding PMD: Invalid array dimension in TX burst for
>>                     802.3ad mode with fast queue leads to SEGFAULT
>>            Product: DPDK
>>            Version: 18.11
>>           Hardware: All
>>                 OS: All
>>             Status: CONFIRMED
>>           Severity: major
>>           Priority: Normal
>>          Component: ethdev
>>           Assignee: dev@dpdk.org
>>           Reporter: p.oltarzewski@gmail.com
>>   Target Milestone: ---
>>
>> DPDK 18.11.1
>>
>> In drivers/net/bonding/rte_eth_bond_pmd.c::bond_ethdev_tx_burst_8023ad,
>> bufs_slave_port_idxs array is defined as follows (lines 1293-1294):
>>
>>     /* Mapping array generated by hash function to map mbufs to slaves */
>>     uint16_t bufs_slave_port_idxs[RTE_MAX_ETHPORTS] = { 0 };
>>
>> Array dimension should be equal to number of packets being transmitted
>> (nb_pkts) - as correctly implemented in
>> rte_eth_bond_pmd.c::bond_ethdev_tx_burst_balance.
>>
>> Invalid array dimension causes overflow when number of transmitted
>> packets is
>> greater than RTE_MAX_ETHPORTS. Some areas of memory end up overwritten
>> (in my
>> particular case, slave_nb_bufs array), which leads to SIGSEGV and crash.
>>
>> To work around the issue, ensure that number of packets transmitted in a
>> single
>> burst is no greater than RTE_MAX_ETHPORTS.
>>
>> To fix it, it should be sufficient to define bufs_slave_port_idxs as a
>> variable-length array, as in bond_ethdev_tx_burst_balance:
>>
>>     /* Mapping array generated by hash function to map mbufs to slaves */
>>     uint16_t bufs_slave_port_idxs[nb_bufs];
>>
>
> I have a series of fixes for this, and on the rx parts as well but did not
> have time to properly check them.
> Would you have some time to test it if I send it ?
>
>
> --
> David Marchand
>