Re: [dpdk-dev] [PATCH v5] ethdev: fix DCB set failure

[Matan Azrad <matan@mellanox.com>]

Hi

 From: Andrew Rybchenko
> CC net/nfp maintainer
> 
> On 5/13/20 8:16 PM, Ting Xu wrote:
> > When rte_eth_dev_rss_hash_conf_get() is called, if the variable
> > rss_conf is not initialized, the pointer member variable rss_key may
> > have a random address, which leads to an error in the following
> > processing. This patch initialized the variable rss_conf to avoid this
> > situation.
> >
> > Fixes: 16321de09396 ("ethdev: allow to get RSS hash functions and
> > key")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Ting Xu <ting.xu@intel.com>
> >
> > ---
> > v4->v5: modify commit log
> > V3->v4: fix build failure
> > v2->v3: move memset to rte_eth_dev_rss_hash_conf_get from testpmd
> > v1->v2: modify commit log, move memset to else leg
> > ---
> >  lib/librte_ethdev/rte_ethdev.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/lib/librte_ethdev/rte_ethdev.c
> > b/lib/librte_ethdev/rte_ethdev.c index 8e10a6fc3..b20c6bb2d 100644
> > --- a/lib/librte_ethdev/rte_ethdev.c
> > +++ b/lib/librte_ethdev/rte_ethdev.c
> > @@ -3552,6 +3552,7 @@ rte_eth_dev_rss_hash_conf_get(uint16_t
> port_id,
> >  	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
> >  	dev = &rte_eth_devices[port_id];
> >  	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rss_hash_conf_get,
> -ENOTSUP);
> > +	memset(rss_conf, 0, sizeof(*rss_conf));
> >  	return eth_err(port_id, (*dev->dev_ops->rss_hash_conf_get)(dev,
> >  								   rss_conf));
> >  }
> >
> 
> The patch breaks getting of RSS key since it resets rss_conf->rss_key to
> NULL, but all drivers treat it as a  pointer to buffer to copy RSS key to.
> Almost all driver just skip RSS key copy if the pointer is NULL.
> 
> I think it should be removed from next-net or improved to reset rss_hf only
> since rss_key_len may be treated as a size of rss_key buffer. The API is not
> clear at the place.
> 
> It looks like net/nfp is the only driver which does not check that that pointer
> is not NULL before coping key to it.


+1

Looks like this breaks also Testpmd  "show port 0 rss-hash key" command.

Matan