Re: [PATCH 01/11] irqchip/gic-v3-its: Free collection mapping on device teardown

[Marc Zyngier]

Hi Zenghui,

On 2019-11-08 14:09, Zenghui Yu wrote:
> Hi Marc,
>
> On 2019/11/6 0:22, Marc Zyngier wrote:
> > Somehow, we forgot to free the collection mapping when tearing down
> > a device, hence slowly leaking mapping arrays as devices get removed
> > from the system. That is, almost never.
> > Just to be safe, properly free the array on device teardown.
> > Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> > ---
> >   drivers/irqchip/irq-gic-v3-its.c | 1 +
> >   1 file changed, 1 insertion(+)
> > diff --git a/drivers/irqchip/irq-gic-v3-its.c 
> > b/drivers/irqchip/irq-gic-v3-its.c
> > index 787e8eec9a7f..07d0bde60e16 100644
> > --- a/drivers/irqchip/irq-gic-v3-its.c
> > +++ b/drivers/irqchip/irq-gic-v3-its.c
> > @@ -2471,6 +2471,7 @@ static void its_free_device(struct its_device 
> > *its_dev)
> >   	raw_spin_lock_irqsave(&its_dev->its->lock, flags);
> >   	list_del(&its_dev->entry);
> >   	raw_spin_unlock_irqrestore(&its_dev->its->lock, flags);
> > +	kfree(its_dev->event_map.col_map);
>
> I agreed that this is the appropriate place to free the collection
> mapping (act as the counterpart of the allocation which happened in
> its_create_device).  But as pointed out by Heyi [1], this will
> introduce a double free issue.  We'd better also drop the kfree()
> in its_irq_domain_free() in this patch?
>
> (I find that it had been dropped in the last patch in your
> irq/gic-5.5-wip branch, but maybe better here.)

Ah, that hunk is in a separate patch that I wasn't really
planning to send for this round. Let me fix the series (again)
and resend it...

Thanks for the heads up,

        M.
--
Jazz is not dead. It just smells funny...