Re: [dpdk-dev] [PATCH v1] app/testpmd: fix DCB set failure in FreeBSD by clang

["Iremonger, Bernard" <bernard.iremonger@intel.com>]

Hi Ting,

> -----Original Message-----
> From: Xu, Ting <ting.xu@intel.com>
> Sent: Tuesday, May 12, 2020 3:17 AM
> To: Yigit, Ferruh <ferruh.yigit@intel.com>; dev@dpdk.org
> Cc: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Xing, Beilei
> <beilei.xing@intel.com>; Iremonger, Bernard
> <bernard.iremonger@intel.com>; stable@dpdk.org; Andrew Rybchenko
> <arybchenko@solarflare.com>; Thomas Monjalon <thomas@monjalon.net>
> Subject: RE: [dpdk-dev] [PATCH v1] app/testpmd: fix DCB set failure in
> FreeBSD by clang
> 
> 
> 
> > -----Original Message-----
> > From: Yigit, Ferruh <ferruh.yigit@intel.com>
> > Sent: Tuesday, May 12, 2020 12:29 AM
> > To: Xu, Ting <ting.xu@intel.com>; dev@dpdk.org
> > Cc: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Xing, Beilei
> > <beilei.xing@intel.com>; Iremonger, Bernard
> > <bernard.iremonger@intel.com>; stable@dpdk.org; Andrew Rybchenko
> > <arybchenko@solarflare.com>; Thomas Monjalon
> <thomas@monjalon.net>
> > Subject: Re: [dpdk-dev] [PATCH v1] app/testpmd: fix DCB set failure in
> > FreeBSD by clang
> >
> > On 5/11/2020 11:25 AM, Ting Xu wrote:
> > > When set DCB in testpmd by clang, there is a segmentation fault.
> > > It is because the local variable rss_conf in get_eth_dcb_conf() is
> > > not cleared, so that the pointer member variable rss_key has a
> > > random address, which leads to an error in the following processing.
> > > This patch initialized the local variable rss_conf to avoid random address.
> >
> > This is nothing really FreeBSD or clang issue, although it may be
> > reproduced that environment, this is a pointer with random value
> > issue. We may drop FreeBSD and clang reference to not create confusion.
> >
> 
> OK,  I will modify the commit log.
> 
> > >
> > > Fixes: b57b66a97ebf ("app/testpmd: support mbuf dynamic flag")
> >
> > This commit looks unrelated, if not can you please explain why above
> > commit causing the issue?
> >
> 
> This is the bad commit the validation team find for this issue. Honestly
> speaking, I did not find the relation between this commit and the issue
> either.
> 
> > > Cc: stable@dpdk.org
> > >
> > > Signed-off-by: Ting Xu <ting.xu@intel.com>
> > > ---
> > >  app/test-pmd/testpmd.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > >
> > > diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c index
> > > 99bacddbf..1276476ca 100644
> > > --- a/app/test-pmd/testpmd.c
> > > +++ b/app/test-pmd/testpmd.c
> > > @@ -3408,6 +3408,7 @@ get_eth_dcb_conf(portid_t pid, struct
> > rte_eth_conf *eth_conf,
> > >  int32_t rc;
> > >  struct rte_eth_rss_conf rss_conf;
> > >
> > > +memset(&rss_conf, 0, sizeof(struct rte_eth_rss_conf));
> >
> > The variable is used in the 'else' leg, memset can be moved there, but
> > more importantly should this be done in the
> 'rte_eth_dev_rss_hash_conf_get()' API.
> >
> > @Andrew, @Thomas,
> >
> > What do you think 'rte_eth_dev_rss_hash_conf_get()' memset the
> 'rss_conf'
> > param before passing it to the PMD? To prevent issues like above in
> > user application.

Seems like a good idea to me, to fix it in rte_eth_dev_rss_hash_conf_get() instead of in testpmd.

> 
> I will move it to the else leg first in the v2 patch. Wait for more comments.
> Thanks!

Regards,

Bernard.