2022-03-25 20:19:31

by baihaowen

Subject: [PATCH] drm/amd/display: Fix pointer dereferenced before checking

The value actual_pix_clk_100Hz is dereferencing pointer pix_clk_params
before pix_clk_params is being null checked. Fix this by assigning
pix_clk_params->requested_pix_clk_100hz to actual_pix_clk_100Hz only if
pix_clk_params is not NULL, otherwise just NULL.

Signed-off-by: Haowen Bai <[email protected]>
---
drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
index 2c7eb98..4db45bb 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
@@ -1162,7 +1162,7 @@ static uint32_t dcn3_get_pix_clk_dividers(
struct pixel_clk_params *pix_clk_params,
struct pll_settings *pll_settings)
{
- unsigned long long actual_pix_clk_100Hz = pix_clk_params->requested_pix_clk_100hz;
+ unsigned long long actual_pix_clk_100Hz = pix_clk_params ? pix_clk_params->requested_pix_clk_100hz : 0;
struct dce110_clk_src *clk_src;

clk_src = TO_DCE110_CLK_SRC(cs);
--
2.7.4

2022-03-25 20:39:51

by Alex Deucher

Subject: Re: [PATCH] drm/amd/display: Fix pointer dereferenced before checking

Applied both patches. Thanks!

Alex

On Thu, Mar 24, 2022 at 9:46 AM Haowen Bai <[email protected]> wrote:
>
> The value actual_pix_clk_100Hz is dereferencing pointer pix_clk_params
> before pix_clk_params is being null checked. Fix this by assigning
> pix_clk_params->requested_pix_clk_100hz to actual_pix_clk_100Hz only if
> pix_clk_params is not NULL, otherwise just NULL.
>
> Signed-off-by: Haowen Bai <[email protected]>
> ---
> drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
> index 2c7eb98..4db45bb 100644
> --- a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
> +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
> @@ -1162,7 +1162,7 @@ static uint32_t dcn3_get_pix_clk_dividers(
> struct pixel_clk_params *pix_clk_params,
> struct pll_settings *pll_settings)
> {
> - unsigned long long actual_pix_clk_100Hz = pix_clk_params->requested_pix_clk_100hz;
> + unsigned long long actual_pix_clk_100Hz = pix_clk_params ? pix_clk_params->requested_pix_clk_100hz : 0;
> struct dce110_clk_src *clk_src;
>
> clk_src = TO_DCE110_CLK_SRC(cs);
> --
> 2.7.4
>

2022-04-07 20:09:50

by Harry Wentland

Subject: Re: [PATCH] drm/amd/display: Fix pointer dereferenced before checking

On 2022-04-07 01:52, Haowen Bai wrote:
> The pointer dc is dereferencing pointer plane_state before plane_state
> is being null checked. Fix this by assigning plane_state->ctx->dc to
> dc only if plane_state is not NULL, otherwise just NULL.
>
> Signed-off-by: Haowen Bai <[email protected]>
> ---
> drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
> index 50820e79d3c4..ee22f4422d26 100644
> --- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
> +++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
> @@ -3211,7 +3211,7 @@ void dcn10_update_pending_status(struct pipe_ctx *pipe_ctx)
> struct dc_plane_state *plane_state = pipe_ctx->plane_state;
> struct timing_generator *tg = pipe_ctx->stream_res.tg;
> bool flip_pending;
> - struct dc *dc = plane_state->ctx->dc;

This has worked for years now, meaning plane_state is never
NULL here. It might be better to drop the NULL check below.

Harry

> + struct dc *dc = plane_state ? plane_state->ctx->dc : NULL;
>
> if (plane_state == NULL)
> return;