linux-kernel - [PATCH] drm/msm/adreno: Assign msm_gpu->pdev earlier to avoid nullptrs

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Message-Id: <20240709-topic-adreno_crash2-v1-1-9def36c3337d@linaro.org>
Date: Tue, 09 Jul 2024 13:15:40 +0200
From: Konrad Dybcio <konrad.dybcio@...aro.org>
To: Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>, 
 Abhinav Kumar <quic_abhinavk@...cinc.com>, 
 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, 
 David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>
Cc: Marijn Suijten <marijn.suijten@...ainline.org>, 
 linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org, 
 freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 Konrad Dybcio <konrad.dybcio@...aro.org>
Subject: [PATCH] drm/msm/adreno: Assign msm_gpu->pdev earlier to avoid
 nullptrs

There are some cases, such as the one uncovered by Commit 46d4efcccc68
("drm/msm/a6xx: Avoid a nullptr dereference when speedbin setting fails")
where

msm_gpu_cleanup() : platform_set_drvdata(gpu->pdev, NULL);

is called on gpu->pdev == NULL, as the GPU device has not been fully
initialized yet.

Turns out that there's more than just the aforementioned path that
causes this to happen (e.g. the case when there's speedbin data in the
catalog, but opp-supported-hw is missing in DT).

Assigning msm_gpu->pdev earlier seems like the least painful solution
to this, therefore do so.

Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
---
There's no fixes tag on purpose, as there doesn't seem to be a good
single commit to blame.
---
 drivers/gpu/drm/msm/adreno/adreno_gpu.c | 1 +
 drivers/gpu/drm/msm/msm_gpu.c           | 1 -
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index 1c6626747b98..949d65437704 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -1083,6 +1083,7 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 	adreno_gpu->chip_id = config->chip_id;
 
 	gpu->allow_relocs = config->info->family < ADRENO_6XX_GEN1;
+	gpu->pdev = pdev;
 
 	/* Only handle the core clock when GMU is not in use (or is absent). */
 	if (adreno_has_gmu_wrapper(adreno_gpu) ||
diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index 3666b42b4ecd..a274b8466423 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -931,7 +931,6 @@ int msm_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 	if (IS_ERR(gpu->gpu_cx))
 		gpu->gpu_cx = NULL;
 
-	gpu->pdev = pdev;
 	platform_set_drvdata(pdev, &gpu->adreno_smmu);
 
 	msm_devfreq_init(gpu);

---
base-commit: 0b58e108042b0ed28a71cd7edf5175999955b233
change-id: 20240709-topic-adreno_crash2-1c9fffd9bce8

Best regards,
-- 
Konrad Dybcio <konrad.dybcio@...aro.org>