On Thu, 9 Mar 2023 17:19:59 +0000
"Dumitrescu, Cristian" <cristian.dumitre...@intel.com> wrote:
> > -----Original Message-----
> > From: Stephen Hemminger <step...@networkplumber.org>
> > Sent: Thursday, March 9, 2023 4:31 PM
> > To: Jangra, Yogesh <yogesh.jan...@intel.com>
> > Cc: dev@dpdk.org; Dumitrescu, Cristian <cristian.dumitre...@intel.com>; R,
> > Kamalakannan <kamalakanna...@intel.com>; Suresh Narayane, Harshad
> > <harshad.suresh.naray...@intel.com>
> > Subject: Re: [PATCH] app/testpmd: fix closing softnic port before ethdev
> > ports
> >
> > On Thu, 9 Mar 2023 14:42:49 +0000
> > Yogesh Jangra <yogesh.jan...@intel.com> wrote:
> >
> > > + /*
> > > + * SoftNIC runs on the sevice core, it uses the resources from
> > > + * the testpmd application. When we run quit command, the
> > testpmd
> > > + * application stops ethdev ports first, SoftNIC will try to
> > > + * access the port and sometimes that result in segmentation
> > > + * error. So first closing the SoftNIC port.
> > > + */
> > > + RTE_ETH_FOREACH_DEV(pt_id) {
> > > + if (!strcmp(ports[pt_id].dev_info.driver_name,
> > "net_softnic")) {
> > > + stop_port(pt_id);
> > > + close_port(pt_id);
> > > + }
> > > + }
> > > +
> >
> > NAK
> > No driver specific hacks please.
> >
> > Instead fix the driver design or bug please.
>
> Hi Stephen,
>
> This is not a Soft NIC driver-specific hack, this is required for working
> around some of the ethdev drivers that don't implement the stop() API
> correctly and free up the device queues or some other internal resources on
> stop() instead of close().
>
> The Soft NIC is a meta-device that sits on top of other "physical" ethdev
> devices, so when the Soft NIC device continues to poll the queues of those
> physical devices after their queues have been freed, the Soft NIC will get a
> segfault. This fix is required to protect against this sort of incorrect
> driver behavior by simply stopping the Soft NIC devices first.
>
> We already have several driver specific branches in the test-pmd for e.g. LAG
> or virtual devices; IMO this small change falls in the same category and it
> should get accepted.
>
> Please let us know if this makes sense to you?
>
> Regards,
> Cristian
If the application has to do this then something is wrong with the architecture.
You aren't propagating state changes through in a safe manner.
Other applications will have same issue.
If LAG or virtual devices have similar problems then a generic solution is
needed.
