2022-02-07 01:04:51

by Christophe JAILLET

Subject: [PATCH] drm/radeon: Avoid open coded arithmetic in memory allocation

kmalloc_array()/kcalloc() should be used to avoid potential overflow when
a multiplication is needed to compute the size of the requested memory.

So turn a kzalloc()+explicit size computation into an equivalent kcalloc().

Signed-off-by: Christophe JAILLET <[email protected]>
---
drivers/gpu/drm/radeon/radeon_atombios.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index 28c4413f4dc8..7b9cc7a9f42f 100644
--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -897,13 +897,13 @@ bool radeon_get_atom_connector_info_from_supported_devices_table(struct
union atom_supported_devices *supported_devices;
int i, j, max_device;
struct bios_connector *bios_connectors;
- size_t bc_size = sizeof(*bios_connectors) * ATOM_MAX_SUPPORTED_DEVICE;
struct radeon_router router;

router.ddc_valid = false;
router.cd_valid = false;

- bios_connectors = kzalloc(bc_size, GFP_KERNEL);
+ bios_connectors = kcalloc(ATOM_MAX_SUPPORTED_DEVICE,
+ sizeof(*bios_connectors), GFP_KERNEL);
if (!bios_connectors)
return false;

--
2.32.0

2022-02-09 11:14:41

by Christian König

Subject: Re: [PATCH] drm/radeon: Avoid open coded arithmetic in memory allocation

Am 05.02.22 um 18:38 schrieb Christophe JAILLET:
> kmalloc_array()/kcalloc() should be used to avoid potential overflow when
> a multiplication is needed to compute the size of the requested memory.
>
> So turn a kzalloc()+explicit size computation into an equivalent kcalloc().
>
> Signed-off-by: Christophe JAILLET <[email protected]>

Reviewed-by: Christian König <[email protected]>

> ---
> drivers/gpu/drm/radeon/radeon_atombios.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
> index 28c4413f4dc8..7b9cc7a9f42f 100644
> --- a/drivers/gpu/drm/radeon/radeon_atombios.c
> +++ b/drivers/gpu/drm/radeon/radeon_atombios.c
> @@ -897,13 +897,13 @@ bool radeon_get_atom_connector_info_from_supported_devices_table(struct
> union atom_supported_devices *supported_devices;
> int i, j, max_device;
> struct bios_connector *bios_connectors;
> - size_t bc_size = sizeof(*bios_connectors) * ATOM_MAX_SUPPORTED_DEVICE;
> struct radeon_router router;
>
> router.ddc_valid = false;
> router.cd_valid = false;
>
> - bios_connectors = kzalloc(bc_size, GFP_KERNEL);
> + bios_connectors = kcalloc(ATOM_MAX_SUPPORTED_DEVICE,
> + sizeof(*bios_connectors), GFP_KERNEL);
> if (!bios_connectors)
> return false;
>