2024-04-12 02:16:23

by Guanrui Huang

[permalink] [raw]
Subject: [PATCH v3] irqchip/gic-v3-its: Fix double free on error

In its_vpe_irq_domain_alloc, when its_vpe_init() returns an error
with i > 0, its_vpe_irq_domain_free may free bitmap and vprop_page,
and then there is a double free in its_vpe_irq_domain_alloc.

Fix it by calling its_vpe_irq_domain_free directly, bitmap and
vprop_page will be freed in this function.

Signed-off-by: Guanrui Huang <[email protected]>
---
drivers/irqchip/irq-gic-v3-its.c | 11 ++---------
1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index fca888b36680..55c83e19719d 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -4521,8 +4521,6 @@ static int its_vpe_irq_domain_alloc(struct irq_domain *domain, unsigned int virq
struct page *vprop_page;
int base, nr_ids, i, err = 0;

- BUG_ON(!vm);
-
bitmap = its_lpi_alloc(roundup_pow_of_two(nr_irqs), &base, &nr_ids);
if (!bitmap)
return -ENOMEM;
@@ -4561,13 +4559,8 @@ static int its_vpe_irq_domain_alloc(struct irq_domain *domain, unsigned int virq
irqd_set_resend_when_in_progress(irq_get_irq_data(virq + i));
}

- if (err) {
- if (i > 0)
- its_vpe_irq_domain_free(domain, virq, i);
-
- its_lpi_free(bitmap, base, nr_ids);
- its_free_prop_table(vprop_page);
- }
+ if (err)
+ its_vpe_irq_domain_free(domain, virq, i);

return err;
}
--
2.36.1



2024-04-12 03:08:09

by Zenghui Yu

[permalink] [raw]
Subject: Re: [PATCH v3] irqchip/gic-v3-its: Fix double free on error

Hi Guanrui,

On 2024/4/12 10:15, Guanrui Huang wrote:
> In its_vpe_irq_domain_alloc, when its_vpe_init() returns an error
> with i > 0, its_vpe_irq_domain_free may free bitmap and vprop_page,
> and then there is a double free in its_vpe_irq_domain_alloc.
>
> Fix it by calling its_vpe_irq_domain_free directly, bitmap and
> vprop_page will be freed in this function.
>
> Signed-off-by: Guanrui Huang <[email protected]>
> ---
> drivers/irqchip/irq-gic-v3-its.c | 11 ++---------
> 1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index fca888b36680..55c83e19719d 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -4521,8 +4521,6 @@ static int its_vpe_irq_domain_alloc(struct irq_domain *domain, unsigned int virq
> struct page *vprop_page;
> int base, nr_ids, i, err = 0;
>
> - BUG_ON(!vm);
> -

The BUG_ON() is indeed useless, though it'd be better to remove it in a
separate patch, with a commit message explaining why it is not needed.

> bitmap = its_lpi_alloc(roundup_pow_of_two(nr_irqs), &base, &nr_ids);
> if (!bitmap)
> return -ENOMEM;
> @@ -4561,13 +4559,8 @@ static int its_vpe_irq_domain_alloc(struct irq_domain *domain, unsigned int virq
> irqd_set_resend_when_in_progress(irq_get_irq_data(virq + i));
> }
>
> - if (err) {
> - if (i > 0)
> - its_vpe_irq_domain_free(domain, virq, i);
> -
> - its_lpi_free(bitmap, base, nr_ids);
> - its_free_prop_table(vprop_page);
> - }
> + if (err)
> + its_vpe_irq_domain_free(domain, virq, i);

This looks good,

Reviewed-by: Zenghui Yu <[email protected]>

Thanks for the fix.

Zenghui

2024-04-15 13:23:56

by Markus Elfring

[permalink] [raw]
Subject: Re: [PATCH v3] irqchip/gic-v3-its: Fix double free on error

> In its_vpe_irq_domain_alloc, when its_vpe_init() returns an error
> with i > 0, its_vpe_irq_domain_free may free bitmap and vprop_page,
> and then there is a double free in its_vpe_irq_domain_alloc.
>
> Fix it by calling its_vpe_irq_domain_free directly, bitmap and
> vprop_page will be freed in this function.

I find this change description improvable.

Would you like to add the tag “Fixes” accordingly?



> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -4521,8 +4521,6 @@ static int its_vpe_irq_domain_alloc(struct irq_domain *domain, unsigned int virq
> struct page *vprop_page;
> int base, nr_ids, i, err = 0;
>
> - BUG_ON(!vm);


Please improve the patch granularity.

See also:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.9-rc4#n81

Regards,
Markus