Re: [PATCH v2 2/4] drm/mediatek: Add cnt checking for coverity issue

Re: [PATCH v2 2/4] drm/mediatek: Add cnt checking for coverity issue

[AngeloGioacchino Del Regno]

Il 13/06/23 13:32, Jason-JH.Lin ha scritto:
> CERT-C Characters and Strings (CERT STR31-C)
> all_drm_priv[cnt] evaluates to an address that could be at negative
> offset of an array.
> 
> In mtk_drm_get_all_drm_priv():
> Guarantee that storage for strings has sufficient space for character
> data and the null terminator.
> 
> So change cnt to unsigned int and check its max value.
> 
> Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
> Fixes: 1ef7ed48356c ("drm/mediatek: Modify mediatek-drm for mt8195 multi mmsys support")

Fixes tag goes before your S-o-b tag.

Anyway,
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

> ---
>   drivers/gpu/drm/mediatek/mtk_drm_drv.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> index 6dcb4ba2466c..fc217e0acd45 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -354,7 +354,7 @@ static bool mtk_drm_get_all_drm_priv(struct device *dev)
>   	const struct of_device_id *of_id;
>   	struct device_node *node;
>   	struct device *drm_dev;
> -	int cnt = 0;
> +	unsigned int cnt = 0;
>   	int i, j;
>   
>   	for_each_child_of_node(phandle->parent, node) {
> @@ -375,6 +375,9 @@ static bool mtk_drm_get_all_drm_priv(struct device *dev)
>   		all_drm_priv[cnt] = dev_get_drvdata(drm_dev);
>   		if (all_drm_priv[cnt] && all_drm_priv[cnt]->mtk_drm_bound)
>   			cnt++;
> +
> +		if (cnt == MAX_CRTC) > +			break;
>   	}
>   
>   	if (drm_priv->data->mmsys_dev_num == cnt) {

Re: [PATCH v2 1/4] drm/mediatek: Remove freeing not dynamic allocated memory

[AngeloGioacchino Del Regno]

Il 13/06/23 13:32, Jason-JH.Lin ha scritto:
> Fixing the coverity issue of:
> mtk_drm_cmdq_pkt_destroy frees address of mtk_crtc->cmdq_handle
> 
> So remove the free function.
> 
> Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
> Fixes: 7627122fd1c0 ("drm/mediatek: Add cmdq_handle in mtk_crtc")

Fixes tag goes before your S-o-b tag.

Anyway,
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

> ---
>   drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 7 ++-----
>   1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> index d40142842f85..8d44f3df116f 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> @@ -116,10 +116,9 @@ static int mtk_drm_cmdq_pkt_create(struct cmdq_client *client, struct cmdq_pkt *
>   	dma_addr_t dma_addr;
>   
>   	pkt->va_base = kzalloc(size, GFP_KERNEL);
> -	if (!pkt->va_base) {
> -		kfree(pkt);
> +	if (!pkt->va_base)
>   		return -ENOMEM;
> -	}
> +
>   	pkt->buf_size = size;
>   	pkt->cl = (void *)client;
>   
> @@ -129,7 +128,6 @@ static int mtk_drm_cmdq_pkt_create(struct cmdq_client *client, struct cmdq_pkt *
>   	if (dma_mapping_error(dev, dma_addr)) {
>   		dev_err(dev, "dma map failed, size=%u\n", (u32)(u64)size);
>   		kfree(pkt->va_base);
> -		kfree(pkt);
>   		return -ENOMEM;
>   	}
>   
> @@ -145,7 +143,6 @@ static void mtk_drm_cmdq_pkt_destroy(struct cmdq_pkt *pkt)
>   	dma_unmap_single(client->chan->mbox->dev, pkt->pa_base, pkt->buf_size,
>   			 DMA_TO_DEVICE);
>   	kfree(pkt->va_base);
> -	kfree(pkt);
>   }
>   #endif
>   

Re: [PATCH v2 3/4] drm/mediatek: Add casting before assign

[AngeloGioacchino Del Regno]

Il 13/06/23 13:32, Jason-JH.Lin ha scritto:
> 1. Add casting before assign to avoid the unintentional integer
>     overflow or unintended sign extension.
> 2. Add a int varriable for multiplier calculation instead of calculating
>     different types multiplier with dma_addr_t varriable directly.
> 
> Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
> Fixes: 1a64a7aff8da ("drm/mediatek: Fix cursor plane no update")
> ---
>   drivers/gpu/drm/mediatek/mtk_drm_gem.c   |  2 +-
>   drivers/gpu/drm/mediatek/mtk_drm_plane.c | 22 +++++++++++++---------
>   2 files changed, 14 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_gem.c b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> index a25b28d3ee90..0c7878bc0b37 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> @@ -121,7 +121,7 @@ int mtk_drm_gem_dumb_create(struct drm_file *file_priv, struct drm_device *dev,
>   	int ret;
>   
>   	args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
> -	args->size = args->pitch * args->height;
> +	args->size = (__u64)args->pitch * args->height;

We could avoid explicit casting here if you do

	args->size = args->pitch;
	args->size *= args->height;

>   
>   	mtk_gem = mtk_drm_gem_create(dev, args->size, false);
>   	if (IS_ERR(mtk_gem))
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_plane.c b/drivers/gpu/drm/mediatek/mtk_drm_plane.c
> index 31f9420aff6f..1cd41454d545 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_plane.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_plane.c
> @@ -145,6 +145,7 @@ static void mtk_plane_update_new_state(struct drm_plane_state *new_state,
>   	dma_addr_t addr;
>   	dma_addr_t hdr_addr = 0;
>   	unsigned int hdr_pitch = 0;
> +	int offset;

...but offset can never be negative, can it?
in that case, this should be unsigned int.

>   
>   	gem = fb->obj[0];
>   	mtk_gem = to_mtk_gem_obj(gem);
> @@ -154,8 +155,10 @@ static void mtk_plane_update_new_state(struct drm_plane_state *new_state,
>   	modifier = fb->modifier;
>   
>   	if (modifier == DRM_FORMAT_MOD_LINEAR) {
> -		addr += (new_state->src.x1 >> 16) * fb->format->cpp[0];
> -		addr += (new_state->src.y1 >> 16) * pitch;
> +		offset = (new_state->src.x1 >> 16) * fb->format->cpp[0];
> +		addr += offset;
> +		offset = (new_state->src.y1 >> 16) * pitch;
> +		addr += offset;
>   	} else {
>   		int width_in_blocks = ALIGN(fb->width, AFBC_DATA_BLOCK_WIDTH)
>   				      / AFBC_DATA_BLOCK_WIDTH;
> @@ -163,21 +166,22 @@ static void mtk_plane_update_new_state(struct drm_plane_state *new_state,
>   				       / AFBC_DATA_BLOCK_HEIGHT;
>   		int x_offset_in_blocks = (new_state->src.x1 >> 16) / AFBC_DATA_BLOCK_WIDTH;
>   		int y_offset_in_blocks = (new_state->src.y1 >> 16) / AFBC_DATA_BLOCK_HEIGHT;
> -		int hdr_size;
> +		int hdr_size, hdr_offset;
>   
>   		hdr_pitch = width_in_blocks * AFBC_HEADER_BLOCK_SIZE;
>   		pitch = width_in_blocks * AFBC_DATA_BLOCK_WIDTH *
>   			AFBC_DATA_BLOCK_HEIGHT * fb->format->cpp[0];
>   
>   		hdr_size = ALIGN(hdr_pitch * height_in_blocks, AFBC_HEADER_ALIGNMENT);
> +		hdr_offset = hdr_pitch * y_offset_in_blocks +
> +			AFBC_HEADER_BLOCK_SIZE * x_offset_in_blocks;
> +		hdr_addr = addr + hdr_offset;
>   
> -		hdr_addr = addr + hdr_pitch * y_offset_in_blocks +
> -			   AFBC_HEADER_BLOCK_SIZE * x_offset_in_blocks;
>   		/* The data plane is offset by 1 additional block. */
> -		addr = addr + hdr_size +
> -		       pitch * y_offset_in_blocks +
> -		       AFBC_DATA_BLOCK_WIDTH * AFBC_DATA_BLOCK_HEIGHT *
> -		       fb->format->cpp[0] * (x_offset_in_blocks + 1);
> +		offset = pitch * y_offset_in_blocks +
> +			 AFBC_DATA_BLOCK_WIDTH * AFBC_DATA_BLOCK_HEIGHT *
> +			 fb->format->cpp[0] * (x_offset_in_blocks + 1);
> +		addr = addr + hdr_size + offset;
>   	}
>   
>   	mtk_plane_state->pending.enable = true;

Re: [PATCH v2 4/4] drm/mediatek: Fix dereference before null check

[AngeloGioacchino Del Regno]

Il 13/06/23 13:32, Jason-JH.Lin ha scritto:
> Null-checking state suggests that it may be null, but it has already
> been dereferenced on drm_atomic_get_new_plane_state(state, plane).
> 
> The parameter state will never be NULL currently, so just remove the
> state is NULL flow in this function.
> 
> Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
> Fixes: 5ddb0bd4ddc3 ("drm/atomic: Pass the full state to planes async atomic check and update")

Fixes before S-o-b...

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>