Re: [PATCH] ide/sii3112: Avoid leaking irqs array

[BALATON Zoltan]

On Mon, 23 Mar 2020, Philippe Mathieu-Daudé wrote:
> On 3/23/20 3:32 PM, BALATON Zoltan wrote:
> > Coverity CID 1421984 reports a leak in allocated irqs, this patch
> > attempts to plug that.
> >
> > Signed-off-by: BALATON Zoltan <address@hidden>
> > ---
> >   hw/ide/sii3112.c | 14 +++++++++++---
> >   1 file changed, 11 insertions(+), 3 deletions(-)
> >
> > diff --git a/hw/ide/sii3112.c b/hw/ide/sii3112.c
> > index 06605d7af2..c886916873 100644
> > --- a/hw/ide/sii3112.c
> > +++ b/hw/ide/sii3112.c
> > @@ -31,6 +31,7 @@ typedef struct SiI3112Regs {
> >   typedef struct SiI3112PCIState {
> >       PCIIDEState i;
> >       MemoryRegion mmio;
> > +    qemu_irq *irqs;
> >       SiI3112Regs regs[2];
> >   } SiI3112PCIState;
> >   @@ -252,7 +253,6 @@ static void sii3112_pci_realize(PCIDevice *dev, Error 
> > **errp)
> >       SiI3112PCIState *d = SII3112_PCI(dev);
> >       PCIIDEState *s = PCI_IDE(dev);
> >       MemoryRegion *mr;
> > -    qemu_irq *irq;
> >       int i;
> >         pci_config_set_interrupt_pin(dev->config, 1);
> > @@ -280,10 +280,10 @@ static void sii3112_pci_realize(PCIDevice *dev, Error 
> > **errp)
> >       memory_region_init_alias(mr, OBJECT(d), "sii3112.bar4", &d->mmio, 0, 
> > 16);
> >       pci_register_bar(dev, 4, PCI_BASE_ADDRESS_SPACE_IO, mr);
> >   -    irq = qemu_allocate_irqs(sii3112_set_irq, d, 2);
> > +    d->irqs = qemu_allocate_irqs(sii3112_set_irq, d, 2);
> >       for (i = 0; i < 2; i++) {
> >           ide_bus_new(&s->bus[i], sizeof(s->bus[i]), DEVICE(dev), i, 1);
> > -        ide_init2(&s->bus[i], irq[i]);
> > +        ide_init2(&s->bus[i], d->irqs[i]);
> >             bmdma_init(&s->bus[i], &s->bmdma[i], s);
> >           s->bmdma[i].bus = &s->bus[i];
> > @@ -291,6 +291,13 @@ static void sii3112_pci_realize(PCIDevice *dev, Error 
> > **errp)
> >       }
> >   }
> >   +static void sii3112_unrealize(DeviceState *dev, Error **errp)
> > +{
> > +    SiI3112PCIState *d = SII3112_PCI(dev);
> > +
> > +    qemu_free_irqs(d->irqs, 2);
>
> You can't do that without calling unrealize() on all the devices in each 
> IDEBus.

What? Those devices are not created in this object so whoever adds them 
later is supposed to free them before this object is unrelaized. Or is 
ownership of those devices silently passed to the the controller when 
adding devices? Anyway, Peter's patch is simpler and should also fix the 
issue so this does not matter any more (other than maybe showing we might 
also leak the devices if their ownership is not clear).

> Apparently there is no code available to do that. Maybe easier to not 
> add any sii3112_unrealize(). Keeping a reference in the state should be 
> enough to silent Coverity.

The idea was to fix the problem not to hide it from Coverity so if it 
can't be fixed it's probably better to be reminded about it than hiding 
it.

Regards,
BALATON Zoltan