From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: Ferruh Yigit <ferruh.yigit@intel.com>
Cc: dev@dpdk.org, Thomas Monjalon <thomas.monjalon@6wind.com>,
Remy Horton <remy.horton@intel.com>
Subject: Re: [dpdk-dev] [PATCH] ethdev: fix wrong memset
Date: Mon, 23 Jan 2017 19:56:10 +0800 [thread overview]
Message-ID: <20170123115610.GG10293@yliu-dev.sh.intel.com> (raw)
In-Reply-To: <20170123114050.GF10293@yliu-dev.sh.intel.com>
On Mon, Jan 23, 2017 at 07:40:50PM +0800, Yuanhan Liu wrote:
> On Mon, Jan 23, 2017 at 11:32:23AM +0000, Ferruh Yigit wrote:
> > On 1/23/2017 11:24 AM, Yuanhan Liu wrote:
> > > On Mon, Jan 23, 2017 at 11:05:25AM +0000, Ferruh Yigit wrote:
> > >>>>>>>> lib/librte_ether/rte_ethdev.c | 2 +-
> > >>>>>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
> > >>>>>>>>
> > >>>>>>>> diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
> > >>>>>>>> index 4790faf..61f44e2 100644
> > >>>>>>>> --- a/lib/librte_ether/rte_ethdev.c
> > >>>>>>>> +++ b/lib/librte_ether/rte_ethdev.c
> > >>>>>>>> @@ -225,7 +225,7 @@ struct rte_eth_dev *
> > >>>>>>>> return NULL;
> > >>>>>>>> }
> > >>>>>>>>
> > >>>>>>>> - memset(&rte_eth_devices[port_id], 0, sizeof(*eth_dev->data));
> > >>>>>>>> + memset(&rte_eth_dev_data[port_id], 0, sizeof(struct rte_eth_dev_data));
> > >>>>>>>
> > >>>>>>> Not directly related to the this issue, but, after fix, this may have
> > >>>>>>> issues with secondary process.
> > >>>>>>>
> > >>>>>>> There were patches sent to fix this.
> > >>>>>>
> > >>>>>> I mean this one:
> > >>>>>> http://dpdk.org/ml/archives/dev/2017-January/054422.html
> > >>>>>
> > >>>>> d948f596fee2 ("ethdev: fix port data mismatched in multiple process
> > >>>>> model") should have fixed it.
> > >>>>
> > >>>> Think about case, where secondary process uses a virtual PMD, which does
> > >>>> a rte_eth_dev_allocate() call, shouldn't this corrupt primary process
> > >>>> device data?
> > >>>
> > >>> Yes, it may. However, I doubt that's the typical usage.
> > >>
> > >> But this is a use case, and broken now,
> > >
> > > I thought it was broken since the beginning?
> >
> > No, memset(&rte_eth_dev_data[port_id], ...) breaks it.
>
> Oh, you were talking about that particular case Remy's patch meant to
> fix.
>
> > >> and fix is known.
> > >
> > > And there is already a fix?
> >
> > http://dpdk.org/ml/archives/dev/2017-January/054422.html
>
> Yes, it should fix that issue.
Well, few more thoughts: it may fix the crash issue Remy saw, but it
looks like more a workaround to me. Basically, if primary and secondary
shares a same port id, they should point to same device. Otherwise,
primary process may use eth_dev->data for a device A, while the
secondary process may use it for another device, as you said, it
could be a vdev.
In such case, there is no way we could continue safely. That said,
the given patch avoids the total reset of eth_dev->data, while it
continues reset the eth_dev->data->name, which is wrong.
So it's not a proper fix.
Again, I think it's more about the usage. If primary starts with
a nic device A, while the secondary starts with a nic device B,
there is no way they could work well (unless they use different
port id).
--yliu
> One question: do Remy or you regularly
> run some multiple process test cases (and with vdev both in primary
> and secondary process)?
next prev parent reply other threads:[~2017-01-23 11:53 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-20 8:04 Yuanhan Liu
2017-01-20 10:20 ` Thomas Monjalon
2017-01-20 10:34 ` Yuanhan Liu
2017-01-20 11:09 ` Ferruh Yigit
2017-01-20 18:05 ` Thomas Monjalon
2017-01-20 11:21 ` Ferruh Yigit
2017-01-20 15:27 ` Ferruh Yigit
2017-01-22 2:45 ` Yuanhan Liu
2017-01-23 9:41 ` Ferruh Yigit
2017-01-23 10:34 ` Yuanhan Liu
2017-01-23 11:05 ` Ferruh Yigit
2017-01-23 11:24 ` Yuanhan Liu
2017-01-23 11:32 ` Ferruh Yigit
2017-01-23 11:40 ` Yuanhan Liu
2017-01-23 11:56 ` Yuanhan Liu [this message]
2017-01-23 12:44 ` Ananyev, Konstantin
2017-01-23 12:52 ` Yuanhan Liu
2017-01-23 13:06 ` Ananyev, Konstantin
2017-01-23 13:09 ` Ferruh Yigit
2017-01-25 11:16 ` Thomas Monjalon
2017-01-28 13:14 ` Yuanhan Liu
2017-01-30 11:07 ` Remy Horton
2017-01-24 8:29 ` Remy Horton
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