Re: [dpdk-dev] [PATCH v3] dev: don't remove devargs that are still referenced

[Thomas Monjalon <thomas@monjalon.net>]

23/11/2018 18:04, Maxime Coquelin:
> Hi,
> 
> On 11/23/18 4:43 PM, Darek Stojaczyk wrote:
> > Even if a device failed to plug, it's still a device
> > object that references the devargs. Those devargs will
> > be freed automatically together with the device, but
> > freeing them any earlier - like it's done in the hotplug
> > error handling path right now - will give us a dangling
> > pointer and a segfault scenario.
> > 
> > Consider the following case:
> >   * secondary process receives the hotplug request IPC message
> >     * devargs are either created or updated
> >     * the bus is scanned
> >       * a new device object is created with the latest devargs
> >     * the device can't be plugged for whatever reason,
> >       bus->plug returns error
> >       * the devargs are freed, even though they're still referenced
> >         by the device object on the bus
> > 
> > For PCI devices, the generic device name comes from
> > a buffer within the devargs. Freeing those will make
> > EAL segfault whenever the device name is checked.
> > 
> > This patch just prevents the hotplug error handling
> > path from removing the devargs when there's a device
> > that references them. This is done by simply exiting
> > early from the hotplug function. As mentioned in the
> > beginning, those devargs will be freed later, together
> > with the device itself.
> > 
> > Fixes: 7e8b26650146 ("eal: fix hotplug add / remove")
> 
> Should you also cc stable?
> Above commit is in since v17.08.
> 
> > Cc: gaetan.rivet@6wind.com
> > Cc: thomas@monjalon.net
> > 
> > Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
> Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Acked-by: Thomas Monjalon <thomas@monjalon.net>

Applied (with rebase), thanks