Re: [dpdk-stable] [PATCH 1/3] bus/vmbus: fix leak on device scan

[Long Li <longli@microsoft.com>]

> Subject: Re: [PATCH 1/3] bus/vmbus: fix leak on device scan
> 
> On Wed, Sep 29, 2021 at 10:57 PM Long Li <longli@microsoft.com> wrote:
> >
> > > Subject: [PATCH 1/3] bus/vmbus: fix leak on device scan
> > >
> > > Caught running ASAN.
> > >
> > > The device name is leaked on scan.
> > > rte_device name field being a const, use the private vmbus struct to
> > > store the device name and point at it.
> > >
> > > Fixes: 831dba47bd36 ("bus/vmbus: add Hyper-V virtual bus support")
> > > Cc: stable@dpdk.org
> > >
> > > Signed-off-by: David Marchand <david.marchand@redhat.com>
> > > ---
> > >  drivers/bus/vmbus/linux/vmbus_bus.c | 5 ++++-
> > >  drivers/bus/vmbus/rte_bus_vmbus.h   | 1 +
> > >  2 files changed, 5 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/bus/vmbus/linux/vmbus_bus.c
> > > b/drivers/bus/vmbus/linux/vmbus_bus.c
> > > index 3c924eee14..d8eb07d398 100644
> > > --- a/drivers/bus/vmbus/linux/vmbus_bus.c
> > > +++ b/drivers/bus/vmbus/linux/vmbus_bus.c
> > > @@ -242,7 +242,7 @@ vmbus_scan_one(const char *name)
> > >               return -1;
> > >
> > >       dev->device.bus = &rte_vmbus_bus.bus;
> > > -     dev->device.name = strdup(name);
> > > +     dev->device.name = dev->name = strdup(name);
> >
> >
> > I suggest not to add a "name" in struct rte_vmbus_device. How about
> defining a local variable in this function, like:
> > dev->device.name = dev_name = strdup(name);
> 
> What is your concern for storing the name?

This name is only used in this function. I see little value of putting it in struct rte_vmbus_device. Am I missing another patch that uses it from struct rte_vmbus_device from another place?

> 
> 
> rte_device name only points at some location where the name is stored.
> In general this storage is in the bus object or (in some buses) the devarg that
> resulted in the rte_device object creation.
> 
> If we won't store the name in the bus object, then we lose the ability to
> release the name later.
> This is probably fine as long as we never release rte_vmbus_device objects
> which is the case atm.
> But I don't understand why vmbus should be an exception when comparing
> to other buses.

I don’t understand why you want to put a name there if it's never used outside vmbus_scan_one().

Long