[PATCH] irqchip/alpine-msi: Fix freeing of interrupts on allocation error path

[PATCH] irqchip/alpine-msi: Fix freeing of interrupts on allocation error path

[Marc Zyngier]

The alpine-msi driver has an interesting allocation error handling,
where it frees the same interrupts repeatedly. Hilarity follows.

This code is probably never executed, but let's fix it nonetheless.

Fixes: e6b78f2c3e14 ("irqchip: Add the Alpine MSIX interrupt controller")
Cc: Tsahee Zidenberg <tsahee@annapurnalabs.com>
Cc: Antoine Tenart <atenart@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/irqchip/irq-alpine-msi.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-alpine-msi.c b/drivers/irqchip/irq-alpine-msi.c
index 23a3b877f7f1..ede02dc2bcd0 100644
--- a/drivers/irqchip/irq-alpine-msi.c
+++ b/drivers/irqchip/irq-alpine-msi.c
@@ -165,8 +165,7 @@ static int alpine_msix_middle_domain_alloc(struct irq_domain *domain,
 	return 0;
 
 err_sgi:
-	while (--i >= 0)
-		irq_domain_free_irqs_parent(domain, virq, i);
+	irq_domain_free_irqs_parent(domain, virq, i - 1);
 	alpine_msix_free_sgi(priv, sgi, nr_irqs);
 	return err;
 }
-- 
2.29.2

Re: [PATCH] irqchip/alpine-msi: Fix freeing of interrupts on allocation error path

[Antoine Tenart]

Hello Marc,

Quoting Marc Zyngier (2020-11-29 14:55:25)
> The alpine-msi driver has an interesting allocation error handling,
> where it frees the same interrupts repeatedly. Hilarity follows.

That's interesting indeed...

> This code is probably never executed, but let's fix it nonetheless.
> 
> Fixes: e6b78f2c3e14 ("irqchip: Add the Alpine MSIX interrupt controller")
> Cc: Tsahee Zidenberg <tsahee@annapurnalabs.com>
> Cc: Antoine Tenart <atenart@kernel.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Antoine Tenart <atenart@kernel.org>

Thanks,
Antoine

> ---
>  drivers/irqchip/irq-alpine-msi.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-alpine-msi.c b/drivers/irqchip/irq-alpine-msi.c
> index 23a3b877f7f1..ede02dc2bcd0 100644
> --- a/drivers/irqchip/irq-alpine-msi.c
> +++ b/drivers/irqchip/irq-alpine-msi.c
> @@ -165,8 +165,7 @@ static int alpine_msix_middle_domain_alloc(struct irq_domain *domain,
>         return 0;
>  
>  err_sgi:
> -       while (--i >= 0)
> -               irq_domain_free_irqs_parent(domain, virq, i);
> +       irq_domain_free_irqs_parent(domain, virq, i - 1);
>         alpine_msix_free_sgi(priv, sgi, nr_irqs);
>         return err;
>  }
> -- 
> 2.29.2
> 

[irqchip: irq/irqchip-next] irqchip/alpine-msi: Fix freeing of interrupts on allocation error path

[irqchip-bot for Marc Zyngier]

The following commit has been merged into the irq/irqchip-next branch of irqchip:

Commit-ID:     3841245e8498a789c65dedd7ffa8fb2fee2c0684
Gitweb:        https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms/3841245e8498a789c65dedd7ffa8fb2fee2c0684
Author:        Marc Zyngier <maz@kernel.org>
AuthorDate:    Sun, 29 Nov 2020 13:55:25 
Committer:     Marc Zyngier <maz@kernel.org>
CommitterDate: Fri, 11 Dec 2020 14:45:22 

irqchip/alpine-msi: Fix freeing of interrupts on allocation error path

The alpine-msi driver has an interesting allocation error handling,
where it frees the same interrupts repeatedly. Hilarity follows.

This code is probably never executed, but let's fix it nonetheless.

Fixes: e6b78f2c3e14 ("irqchip: Add the Alpine MSIX interrupt controller")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Antoine Tenart <atenart@kernel.org>
Cc: Tsahee Zidenberg <tsahee@annapurnalabs.com>
Cc: Antoine Tenart <atenart@kernel.org>
Link: https://lore.kernel.org/r/20201129135525.396671-1-maz@kernel.org
---
 drivers/irqchip/irq-alpine-msi.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-alpine-msi.c b/drivers/irqchip/irq-alpine-msi.c
index 23a3b87..ede02dc 100644
--- a/drivers/irqchip/irq-alpine-msi.c
+++ b/drivers/irqchip/irq-alpine-msi.c
@@ -165,8 +165,7 @@ static int alpine_msix_middle_domain_alloc(struct irq_domain *domain,
 	return 0;
 
 err_sgi:
-	while (--i >= 0)
-		irq_domain_free_irqs_parent(domain, virq, i);
+	irq_domain_free_irqs_parent(domain, virq, i - 1);
 	alpine_msix_free_sgi(priv, sgi, nr_irqs);
 	return err;
 }

Re: [PATCH] irqchip/alpine-msi: Fix freeing of interrupts on allocation error path

[Marc Zyngier]

On Sun, 29 Nov 2020 13:55:25 +0000, Marc Zyngier wrote:
> The alpine-msi driver has an interesting allocation error handling,
> where it frees the same interrupts repeatedly. Hilarity follows.
> 
> This code is probably never executed, but let's fix it nonetheless.

Applied to irq/irqchip-next, thanks!

[1/1] irqchip/alpine-msi: Fix freeing of interrupts on allocation error path
      commit: 3841245e8498a789c65dedd7ffa8fb2fee2c0684

Cheers,

	M.
-- 
Without deviation from the norm, progress is not possible.