[PATCH 01/11] drm/msm: fail the snapshot init when its worker cannot be created

[Dmitry Baryshkov]

msm_disp_snapshot_init() only logs a failure of kthread_run_worker() and
returns success, leaving the error pointer in kms->dump_worker.  Both of
its users then dereference it: msm_disp_snapshot_state() queues the dump
work on it on the first display error, and msm_disp_snapshot_destroy()
only checks the pointer for NULL before passing it to
kthread_destroy_worker().

Clear the pointer and return the error instead, so that the KMS init
fails rather than leaving a snapshot facility which crashes when used.

Fixes: 98659487b845 ("drm/msm: add support to take dpu snapshot")
Assisted-by: LLM
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/msm/disp/msm_disp_snapshot.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/msm_disp_snapshot.c b/drivers/gpu/drm/msm/disp/msm_disp_snapshot.c
index d99771684728..d1b10656e41a 100644
--- a/drivers/gpu/drm/msm/disp/msm_disp_snapshot.c
+++ b/drivers/gpu/drm/msm/disp/msm_disp_snapshot.c
@@ -98,6 +98,7 @@ int msm_disp_snapshot_init(struct drm_device *drm_dev)
 {
 	struct msm_drm_private *priv;
 	struct msm_kms *kms;
+	int ret;
 
 	if (!drm_dev) {
 		DRM_ERROR("invalid params\n");
@@ -110,12 +111,21 @@ int msm_disp_snapshot_init(struct drm_device *drm_dev)
 	mutex_init(&kms->dump_mutex);
 
 	kms->dump_worker = kthread_run_worker(0, "%s", "disp_snapshot");
-	if (IS_ERR(kms->dump_worker))
+	if (IS_ERR(kms->dump_worker)) {
+		ret = PTR_ERR(kms->dump_worker);
 		DRM_ERROR("failed to create disp state task\n");
+		goto err_destroy_mutex;
+	}
 
 	kthread_init_work(&kms->dump_work, _msm_disp_snapshot_work);
 
 	return 0;
+
+err_destroy_mutex:
+	kms->dump_worker = NULL;
+	mutex_destroy(&kms->dump_mutex);
+
+	return ret;
 }
 
 void msm_disp_snapshot_destroy(struct drm_device *drm_dev)

-- 
2.47.3