Re: [PATCH][next] drm/amdgpu/powerplay: fix dereference before null check of pointer hwmgr

From: Alex Deucher
Date: Mon Nov 18 2019 - 12:48:05 EST


Applied. Thanks!

Alex

On Mon, Nov 18, 2019 at 1:56 AM Quan, Evan <Evan.Quan@xxxxxxx> wrote:
>
> Reviewed-by: Evan Quan <evan.quan@xxxxxxx>
>
> -----Original Message-----
> From: Colin King <colin.king@xxxxxxxxxxxxx>
> Sent: Friday, November 15, 2019 5:48 PM
> To: Rex Zhu <rex.zhu@xxxxxxx>; Quan, Evan <Evan.Quan@xxxxxxx>; Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Koenig, Christian <Christian.Koenig@xxxxxxx>; Zhou, David(ChunMing) <David1.Zhou@xxxxxxx>; David Airlie <airlied@xxxxxxxx>; Daniel Vetter <daniel@xxxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Cc: kernel-janitors@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH][next] drm/amdgpu/powerplay: fix dereference before null check of pointer hwmgr
>
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> The assignment of adev dereferences pointer hwmgr before hwmgr is null checked, hence there is a potential null pointer deference issue. Fix this by assigning adev after the null check.
>
> Addresses-Coverity: ("Dereference before null check")
> Fixes: 0896d2f7ba4d ("drm/amdgpu/powerplay: properly set PP_GFXOFF_MASK")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/amd/powerplay/hwmgr/hwmgr.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/hwmgr.c
> index 443625c83ec9..d2909c91d65b 100644
> --- a/drivers/gpu/drm/amd/powerplay/hwmgr/hwmgr.c
> +++ b/drivers/gpu/drm/amd/powerplay/hwmgr/hwmgr.c
> @@ -81,7 +81,7 @@ static void hwmgr_init_workload_prority(struct pp_hwmgr *hwmgr)
>
> int hwmgr_early_init(struct pp_hwmgr *hwmgr) {
> - struct amdgpu_device *adev = hwmgr->adev;
> + struct amdgpu_device *adev;
>
> if (!hwmgr)
> return -EINVAL;
> @@ -96,6 +96,8 @@ int hwmgr_early_init(struct pp_hwmgr *hwmgr)
> hwmgr_init_workload_prority(hwmgr);
> hwmgr->gfxoff_state_changed_by_workload = false;
>
> + adev = hwmgr->adev;
> +
> switch (hwmgr->chip_family) {
> case AMDGPU_FAMILY_CI:
> adev->pm.pp_feature &= ~PP_GFXOFF_MASK;
> --
> 2.20.1
>
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