2024-01-12 06:41:42

by Kunwu Chan

Subject: [PATCH] vfio/platform: Remove unnecessary free in vfio_set_trigger

commit 57f972e2b341 ("vfio/platform: trigger an interrupt via eventfd")
add 'name' as member for vfio_platform_irq,it's initialed by kasprintf,
so there is no need to free it before initializing.

Fixes: 57f972e2b341 ("vfio/platform: trigger an interrupt via eventfd")
Signed-off-by: Kunwu Chan <[email protected]>
---
drivers/vfio/platform/vfio_platform_irq.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index 61a1bfb68ac7..5e3fd1926366 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -179,7 +179,6 @@ static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
if (irq->trigger) {
irq_clear_status_flags(irq->hwirq, IRQ_NOAUTOEN);
free_irq(irq->hwirq, irq);
- kfree(irq->name);
eventfd_ctx_put(irq->trigger);
irq->trigger = NULL;
}
--
2.39.2

2024-01-12 15:35:40

by Alex Williamson

Subject: Re: [PATCH] vfio/platform: Remove unnecessary free in vfio_set_trigger

On Fri, 12 Jan 2024 14:41:07 +0800
Kunwu Chan <[email protected]> wrote:

> commit 57f972e2b341 ("vfio/platform: trigger an interrupt via eventfd")
> add 'name' as member for vfio_platform_irq,it's initialed by kasprintf,
> so there is no need to free it before initializing.

What?! Just look at the call path where vfio_set_trigger() is called
with a valid fd and existing trigger. This change would leak irq->name
as it's reallocated via kasprintf(). Thanks,

Alex

> Fixes: 57f972e2b341 ("vfio/platform: trigger an interrupt via eventfd")
> Signed-off-by: Kunwu Chan <[email protected]>
> ---
> drivers/vfio/platform/vfio_platform_irq.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
> index 61a1bfb68ac7..5e3fd1926366 100644
> --- a/drivers/vfio/platform/vfio_platform_irq.c
> +++ b/drivers/vfio/platform/vfio_platform_irq.c
> @@ -179,7 +179,6 @@ static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
> if (irq->trigger) {
> irq_clear_status_flags(irq->hwirq, IRQ_NOAUTOEN);
> free_irq(irq->hwirq, irq);
> - kfree(irq->name);
> eventfd_ctx_put(irq->trigger);
> irq->trigger = NULL;
> }

2024-01-15 06:09:03

by Kunwu Chan

Subject: Re: [PATCH] vfio/platform: Remove unnecessary free in vfio_set_trigger

On 2024/1/12 23:34, Alex Williamson wrote:
> On Fri, 12 Jan 2024 14:41:07 +0800
> Kunwu Chan <[email protected]> wrote:
>
>> commit 57f972e2b341 ("vfio/platform: trigger an interrupt via eventfd")
>> add 'name' as member for vfio_platform_irq,it's initialed by kasprintf,
>> so there is no need to free it before initializing.
>
> What?! Just look at the call path where vfio_set_trigger() is called
> with a valid fd and existing trigger. This change would leak irq->name
> as it's reallocated via kasprintf(). Thanks,
>
> Alex
>
>> Fixes: 57f972e2b341 ("vfio/platform: trigger an interrupt via eventfd")
>> Signed-off-by: Kunwu Chan <[email protected]>
>> ---
>> drivers/vfio/platform/vfio_platform_irq.c | 1 -
>> 1 file changed, 1 deletion(-)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
>> index 61a1bfb68ac7..5e3fd1926366 100644
>> --- a/drivers/vfio/platform/vfio_platform_irq.c
>> +++ b/drivers/vfio/platform/vfio_platform_irq.c
>> @@ -179,7 +179,6 @@ static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
>> if (irq->trigger) {
>> irq_clear_status_flags(irq->hwirq, IRQ_NOAUTOEN);
>> free_irq(irq->hwirq, irq);
>> - kfree(irq->name);
>> eventfd_ctx_put(irq->trigger);
>> irq->trigger = NULL;
>> }
>
Thanks for your reply.

It's my bad.I misunderstood. Sorry to bother you.
--
Thanks,
Kunwu