Re: [PATCH] bugfix: irq: Avoid covering object refcount of qemu_irq

[Peter Maydell]

On Mon, 27 Jul 2020 at 14:03, Keqian Zhu <zhukeqian1@huawei.com> wrote:
>
> Avoid covering object refcount of qemu_irq, otherwise it may causes
> memory leak.
>
> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> ---
>  hw/core/irq.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/hw/core/irq.c b/hw/core/irq.c
> index fb3045b912..59af4dfc74 100644
> --- a/hw/core/irq.c
> +++ b/hw/core/irq.c
> @@ -125,7 +125,9 @@ void qemu_irq_intercept_in(qemu_irq *gpio_in, 
> qemu_irq_handler handler, int n)
>      int i;
>      qemu_irq *old_irqs = qemu_allocate_irqs(NULL, NULL, n);
>      for (i = 0; i < n; i++) {
> -        *old_irqs[i] = *gpio_in[i];
> +        old_irqs[i]->handler = gpio_in[i]->handler;
> +        old_irqs[i]->opaque = gpio_in[i]->opaque;
> +
>          gpio_in[i]->handler = handler;
>          gpio_in[i]->opaque = &old_irqs[i];
>      }

This function is leaky by design, because it doesn't do anything
with the old_irqs array and there's no function for un-intercepting
the IRQs (which would need to free that memory). This is not ideal
but OK because it's only used in the test suite.

Is there a specific bug you're trying to fix here?

thanks
-- PMM