Re: [PATCH] virtio-serial-bus: fix memory leak while attach virtio-serial-bus

[Amit Shah <amit@infradead.org>]

On Tue, 2019-12-03 at 00:37 -0500, Michael S. Tsirkin wrote:
> On Tue, Dec 03, 2019 at 08:53:42AM +0800, pannengyuan wrote:
> > 
> > 
> > On 2019/12/2 21:58, Laurent Vivier wrote:
> > > On 02/12/2019 12:15, pannengyuan@huawei.com wrote:
> > > > From: PanNengyuan <pannengyuan@huawei.com>
> > > > 
> > > > ivqs/ovqs/c_ivq/c_ovq is forgot to cleanup in
> > > > virtio_serial_device_unrealize, the memory leak stack is as
> > > > bellow:
> > > > 
> > > > Direct leak of 1290240 byte(s) in 180 object(s) allocated from:
> > > >     #0 0x7fc9bfc27560 in calloc
> > > > (/usr/lib64/libasan.so.3+0xc7560)
> > > >     #1 0x7fc9bed6f015 in g_malloc0 (/usr/lib64/libglib-
> > > > 2.0.so.0+0x50015)
> > > >     #2 0x5650e02b83e7 in virtio_add_queue /mnt/sdb/qemu-4.2.0-
> > > > rc0/hw/virtio/virtio.c:2327
> > > >     #3 0x5650e02847b5 in virtio_serial_device_realize
> > > > /mnt/sdb/qemu-4.2.0-rc0/hw/char/virtio-serial-bus.c:1089
> > > >     #4 0x5650e02b56a7 in virtio_device_realize /mnt/sdb/qemu-
> > > > 4.2.0-rc0/hw/virtio/virtio.c:3504
> > > >     #5 0x5650e03bf031 in device_set_realized /mnt/sdb/qemu-
> > > > 4.2.0-rc0/hw/core/qdev.c:876
> > > >     #6 0x5650e0531efd in property_set_bool /mnt/sdb/qemu-4.2.0-
> > > > rc0/qom/object.c:2080
> > > >     #7 0x5650e053650e in object_property_set_qobject
> > > > /mnt/sdb/qemu-4.2.0-rc0/qom/qom-qobject.c:26
> > > >     #8 0x5650e0533e14 in object_property_set_bool
> > > > /mnt/sdb/qemu-4.2.0-rc0/qom/object.c:1338
> > > >     #9 0x5650e04c0e37 in virtio_pci_realize /mnt/sdb/qemu-
> > > > 4.2.0-rc0/hw/virtio/virtio-pci.c:1801
> > > > 
> > > > Reported-by: Euler Robot <euler.robot@huawei.com>
> > > > Signed-off-by: PanNengyuan <pannengyuan@huawei.com>
> > > > ---
> > > >  hw/char/virtio-serial-bus.c | 6 ++++++
> > > >  1 file changed, 6 insertions(+)
> > > > 
> > > > diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-
> > > > serial-bus.c
> > > > index 3325904..da9019a 100644
> > > > --- a/hw/char/virtio-serial-bus.c
> > > > +++ b/hw/char/virtio-serial-bus.c
> > > > @@ -1126,9 +1126,15 @@ static void
> > > > virtio_serial_device_unrealize(DeviceState *dev, Error **errp)
> > > >  {
> > > >      VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> > > >      VirtIOSerial *vser = VIRTIO_SERIAL(dev);
> > > > +    int i;
> > > >  
> > > >      QLIST_REMOVE(vser, next);
> > > >  
> > > > +    for (i = 0; i <= vser->bus.max_nr_ports; i++) {
> > > > +        virtio_del_queue(vdev, 2 * i);
> > > > +        virtio_del_queue(vdev, 2 * i + 1);
> > > > +    }
> > > > +
> > > 
> > > According to virtio_serial_device_realize() and the number of
> > > virtio_add_queue(), I think you have more queues to delete:
> > > 
> > >   4 + 2 * vser->bus.max_nr_ports
> > > 
> > > (for vser->ivqs[0], vser->ovqs[0], vser->c_ivq, vser->c_ovq,
> > > vser->ivqs[i], vser->ovqs[i]).
> > > 
> > > Thanks,
> > > Laurent
> > > 
> > > 
> > 
> > Thanks, but I think the queues is correct, the queues in
> > virtio_serial_device_realize is as follow:
> > 
> > // here is 2
> > vser->ivqs[0] = virtio_add_queue(vdev, 128, handle_input);
> > vser->ovqs[0] = virtio_add_queue(vdev, 128, handle_output);
> > 
> > // here is 2
> > vser->c_ivq = virtio_add_queue(vdev, 32, control_in);
> > vser->c_ovq = virtio_add_queue(vdev, 32, control_out);
> > 
> > // here 2 * (max_nr_ports - 1)  ----- i is from 1 to max_nr_ports -
> > 1
> > for (i = 1; i < vser->bus.max_nr_ports; i++) {
> >     vser->ivqs[i] = virtio_add_queue(vdev, 128, handle_input);
> >     vser->ovqs[i] = virtio_add_queue(vdev, 128, handle_output);
> > }
> > 
> > so the total queues number is:  2 * (vser->bus.max_nr_ports + 1)
> 
> Rather than worry about this, I posted a patch adding
> virtio_delete_queue.
> How about reusing that, and just using ivqs/ovqs pointers?

Nice, that's cleaner.

>