drm/vc4: tests: Stop allocating the state in test init

The vc4-pv-muxing-combinations and vc5-pv-muxing-combinations test
suites use a common test init function which, in part, allocates the
drm atomic state the test will use.

That allocation relies on  drm_kunit_helper_atomic_state_alloc(), and
thus requires a struct drm_modeset_acquire_ctx. This context will then
be stored in the allocated state->acquire_ctx field.

However, the context is local to the test init function, and is cleared
as soon as drm_kunit_helper_atomic_state_alloc() is done. We thus end up
with an dangling pointer to a cleared context in state->acquire_ctx for
our test to consumes.

We should really allocate the context and the state in the test
functions, so we can also control when we're done with it.

Fixes: 30188df0c3 ("drm/tests: Drop drm_kunit_helper_acquire_ctx_alloc()")
Reviewed-by: Maíra Canal <mcanal@igalia.com>
Link: https://lore.kernel.org/r/20250403-drm-vc4-kunit-failures-v2-3-e09195cc8840@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>

drivers/gpu/drm/vc4/tests/vc4_test_pv_muxing.c

@@ -20,7 +20,6 @@
 
 struct pv_muxing_priv {
 	struct vc4_dev *vc4;
-	struct drm_atomic_state *state;
 };
 
 static bool check_fifo_conflict(struct kunit *test,
@@ -677,10 +676,19 @@ static void drm_vc4_test_pv_muxing(struct kunit *test)
 {
 	const struct pv_muxing_param *params = test->param_value;
 	const struct pv_muxing_priv *priv = test->priv;
-	struct drm_atomic_state *state = priv->state;
+	struct drm_modeset_acquire_ctx ctx;
+	struct drm_atomic_state *state;
+	struct drm_device *drm;
+	struct vc4_dev *vc4;
 	unsigned int i;
 	int ret;
 
+	drm_modeset_acquire_init(&ctx, 0);
+
+	vc4 = priv->vc4;
+	drm = &vc4->base;
+	state = drm_kunit_helper_atomic_state_alloc(test, drm, &ctx);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, state);
 	for (i = 0; i < params->nencoders; i++) {
 		enum vc4_encoder_type enc_type = params->encoders[i];
 
@@ -700,16 +708,29 @@ static void drm_vc4_test_pv_muxing(struct kunit *test)
 		KUNIT_EXPECT_TRUE(test, check_channel_for_encoder(test, state, enc_type,
 								  params->check_fn));
 	}
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
 }
 
 static void drm_vc4_test_pv_muxing_invalid(struct kunit *test)
 {
 	const struct pv_muxing_param *params = test->param_value;
 	const struct pv_muxing_priv *priv = test->priv;
-	struct drm_atomic_state *state = priv->state;
+	struct drm_modeset_acquire_ctx ctx;
+	struct drm_atomic_state *state;
+	struct drm_device *drm;
+	struct vc4_dev *vc4;
 	unsigned int i;
 	int ret;
 
+	drm_modeset_acquire_init(&ctx, 0);
+
+	vc4 = priv->vc4;
+	drm = &vc4->base;
+	state = drm_kunit_helper_atomic_state_alloc(test, drm, &ctx);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, state);
+
 	for (i = 0; i < params->nencoders; i++) {
 		enum vc4_encoder_type enc_type = params->encoders[i];
 
@@ -719,14 +740,15 @@ static void drm_vc4_test_pv_muxing_invalid(struct kunit *test)
 
 	ret = drm_atomic_check_only(state);
 	KUNIT_EXPECT_LT(test, ret, 0);
+
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
 }
 
 static int vc4_pv_muxing_test_init(struct kunit *test)
 {
 	const struct pv_muxing_param *params = test->param_value;
-	struct drm_modeset_acquire_ctx ctx;
 	struct pv_muxing_priv *priv;
-	struct drm_device *drm;
 	struct vc4_dev *vc4;
 
 	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
@@ -737,15 +759,6 @@ static int vc4_pv_muxing_test_init(struct kunit *test)
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, vc4);
 	priv->vc4 = vc4;
 
-	drm_modeset_acquire_init(&ctx, 0);
-
-	drm = &vc4->base;
-	priv->state = drm_kunit_helper_atomic_state_alloc(test, drm, &ctx);
-	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->state);
-
-	drm_modeset_drop_locks(&ctx);
-	drm_modeset_acquire_fini(&ctx);
-
 	return 0;
 }