Re: [PATCHv3] drm/amdkfd: Remove vla

[Kees Cook <keescook@chromium.org>]

On Fri, Apr 13, 2018 at 2:24 PM, Laura Abbott <labbott@redhat.com> wrote:
>
> There's an ongoing effort to remove VLAs[1] from the kernel to eventually
> turn on -Wvla. Switch to a constant value that covers all hardware.
>
> [1] https://lkml.org/lkml/2018/3/7/621
>
> Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
> Acked-by: Christian König <christian.koenig@amd.com>
> Signed-off-by: Laura Abbott <labbott@redhat.com>

Friendly ping -- I don't see this in -next yet. Oded, does this look
okay to apply?

Thanks!

-Kees

> ---
> v3: Introduced a #define for the max value, switched to pr_err_once to
> avoid log flood, switched to sizeof(array) per private suggestion.
> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c | 8 +++++---
>  drivers/gpu/drm/amd/amdkfd/kfd_priv.h      | 2 ++
>  2 files changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c b/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c
> index 035c351f47c5..db6d9336b80d 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c
> @@ -139,10 +139,12 @@ static void interrupt_wq(struct work_struct *work)
>  {
>         struct kfd_dev *dev = container_of(work, struct kfd_dev,
>                                                 interrupt_work);
> +       uint32_t ih_ring_entry[KFD_MAX_RING_ENTRY_SIZE];
>
> -       uint32_t ih_ring_entry[DIV_ROUND_UP(
> -                               dev->device_info->ih_ring_entry_size,
> -                               sizeof(uint32_t))];
> +       if (dev->device_info->ih_ring_entry_size > sizeof(ih_ring_entry)) {
> +               dev_err_once(kfd_chardev(), "Ring entry too small\n");
> +               return;
> +       }
>
>         while (dequeue_ih_ring_entry(dev, ih_ring_entry))
>                 dev->device_info->event_interrupt_class->interrupt_wq(dev,
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> index 96a9cc0f02c9..a90db05dfe61 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> @@ -39,6 +39,8 @@
>
>  #include "amd_shared.h"
>
> +#define KFD_MAX_RING_ENTRY_SIZE        8
> +
>  #define KFD_SYSFS_FILE_MODE 0444
>
>  #define KFD_MMAP_DOORBELL_MASK 0x8000000000000ull
> --
> 2.14.3
>



-- 
Kees Cook
Pixel Security