[dpdk-dev] Segfault seen in netmap_compat app on Power8

gowrishankar muthukrishnan gowrishankar.m at linux.vnet.ibm.com
Thu Apr 6 11:36:03 CEST 2017

With gcc 6.3.0, I find this app functioning w/o crash.

Did disabling gcc optimization help ? (set EXTRA_CFLAGS='-O0' before 

On Thursday 06 April 2017 02:34 PM, Rahul Lakkireddy wrote:
> Hi,
> For netmap_compat bridge application on Power8, in netmap_regif
> function, the assignment to nmif->ring_ofs[i] is not getting reflected
> immediately.
> As a result, the subsequent call to netmap_ring_setup ends up writing
> data at wrong offset. This causes segfault in the app.
> If we print the nmif->ring_ofs[i] after assignment, then, we see the
> correct offset and application starts fine.
> So, probably, some kind of barrier or mechanism to flush write is
> required on Power8?
> BTW, this was tried with ToT dpdk git tree on RHEL 7.3 having below
> gcc version:
> gcc version 4.8.5 20150623 (Red Hat 4.8.5-11) (GCC)
> Thanks,
> Rahul

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