2021-09-29 12:21:03

by Colin King

Subject: [PATCH] drm/msm: Fix null pointer dereference on pointer edp

From: Colin Ian King <[email protected]>

The initialization of pointer dev dereferences pointer edp before
edp is null checked, so there is a potential null pointer deference
issue. Fix this by only dereferencing edp after edp has been null
checked.

Addresses-Coverity: ("Dereference before null check")
Fixes: ab5b0107ccf3 ("drm/msm: Initial add eDP support in msm drm driver (v5)")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/gpu/drm/msm/edp/edp_ctrl.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/edp/edp_ctrl.c b/drivers/gpu/drm/msm/edp/edp_ctrl.c
index 4fb397ee7c84..fe1366b4c49f 100644
--- a/drivers/gpu/drm/msm/edp/edp_ctrl.c
+++ b/drivers/gpu/drm/msm/edp/edp_ctrl.c
@@ -1116,7 +1116,7 @@ void msm_edp_ctrl_power(struct edp_ctrl *ctrl, bool on)
int msm_edp_ctrl_init(struct msm_edp *edp)
{
struct edp_ctrl *ctrl = NULL;
- struct device *dev = &edp->pdev->dev;
+ struct device *dev;
int ret;

if (!edp) {
@@ -1124,6 +1124,7 @@ int msm_edp_ctrl_init(struct msm_edp *edp)
return -EINVAL;
}

+ dev = &edp->pdev->dev;
ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
if (!ctrl)
return -ENOMEM;
--
2.32.0

2021-10-01 20:01:49

by Dmitry Baryshkov

Subject: Re: [PATCH] drm/msm: Fix null pointer dereference on pointer edp

On 29/09/2021 15:18, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> The initialization of pointer dev dereferences pointer edp before
> edp is null checked, so there is a potential null pointer deference
> issue. Fix this by only dereferencing edp after edp has been null
> checked.
>
> Addresses-Coverity: ("Dereference before null check")
> Fixes: ab5b0107ccf3 ("drm/msm: Initial add eDP support in msm drm driver (v5)")
> Signed-off-by: Colin Ian King <[email protected]>

Reviewed-by: Dmitry Baryshkov <[email protected]>

> ---
> drivers/gpu/drm/msm/edp/edp_ctrl.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/edp/edp_ctrl.c b/drivers/gpu/drm/msm/edp/edp_ctrl.c
> index 4fb397ee7c84..fe1366b4c49f 100644
> --- a/drivers/gpu/drm/msm/edp/edp_ctrl.c
> +++ b/drivers/gpu/drm/msm/edp/edp_ctrl.c
> @@ -1116,7 +1116,7 @@ void msm_edp_ctrl_power(struct edp_ctrl *ctrl, bool on)
> int msm_edp_ctrl_init(struct msm_edp *edp)
> {
> struct edp_ctrl *ctrl = NULL;
> - struct device *dev = &edp->pdev->dev;
> + struct device *dev;
> int ret;
>
> if (!edp) {
> @@ -1124,6 +1124,7 @@ int msm_edp_ctrl_init(struct msm_edp *edp)
> return -EINVAL;
> }
>
> + dev = &edp->pdev->dev;
> ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
> if (!ctrl)
> return -ENOMEM;
>


--
With best wishes
Dmitry