drm/tests: Alloc drm_device on drm_exec tests

The drm_exec tests where crashing[0] because of a null dereference. This
is caused by a new access of the `driver` attribute of `struct
drm_driver` on drm_gem_private_object_init(). Alloc the drm_device to
fix that.

[0]
[15:05:24] ================== drm_exec (6 subtests) ===================
[15:05:24] [PASSED] sanitycheck
^CERROR:root:Build interruption occurred. Cleaning console.
[15:05:50] [ERROR] Test: drm_exec: missing expected subtest!
[15:05:50] BUG: kernel NULL pointer dereference, address: 00000000000000b0
[15:05:50] #PF: supervisor read access in kernel mode
[15:05:50] #PF: error_code(0x0000) - not-present page
[15:05:50] PGD 0 P4D 0
[15:05:50] Oops: 0000 [#1] PREEMPT NOPTI
[15:05:50] CPU: 0 PID: 23 Comm: kunit_try_catch Tainted: G                 N 6.4.0-rc7-02032-ge6303f32 #69
[15:05:50] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc37 04/01/2014
[15:05:50] RIP: 0010:drm_gem_private_object_init+0x60/0xc0

Fixes: e6303f32 ("drm: manager to keep track of GPUs VA mappings")
Signed-off-by: Arthur Grillo <arthurgrillo@riseup.net>
Tested-by: Danilo Krummrich <dakr@redhat.com>
Acked-by: Danilo Krummrich <dakr@redhat.com>
Reviewed-by: Maíra Canal <mcanal@igalia.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230731182241.240556-1-arthurgrillo@riseup.net

drivers/gpu/drm/tests/drm_exec_test.c

@@ -12,11 +12,35 @@
 
 #include <drm/drm_exec.h>
 #include <drm/drm_device.h>
+#include <drm/drm_drv.h>
 #include <drm/drm_gem.h>
+#include <drm/drm_kunit_helpers.h>
 
 #include "../lib/drm_random.h"
 
-static struct drm_device dev;
+struct drm_exec_priv {
+	struct device *dev;
+	struct drm_device *drm;
+};
+
+static int drm_exec_test_init(struct kunit *test)
+{
+	struct drm_exec_priv *priv;
+
+	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
+
+	test->priv = priv;
+
+	priv->dev = drm_kunit_helper_alloc_device(test);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->dev);
+
+	priv->drm = __drm_kunit_helper_alloc_drm_device(test, priv->dev, sizeof(*priv->drm), 0,
+							DRIVER_MODESET);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->drm);
+
+	return 0;
+}
 
 static void sanitycheck(struct kunit *test)
 {
@@ -29,11 +53,12 @@ static void sanitycheck(struct kunit *test)
 
 static void test_lock(struct kunit *test)
 {
+	struct drm_exec_priv *priv = test->priv;
 	struct drm_gem_object gobj = { };
 	struct drm_exec exec;
 	int ret;
 
-	drm_gem_private_object_init(&dev, &gobj, PAGE_SIZE);
+	drm_gem_private_object_init(priv->drm, &gobj, PAGE_SIZE);
 
 	drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT);
 	drm_exec_until_all_locked(&exec) {
@@ -48,11 +73,12 @@ static void test_lock(struct kunit *test)
 
 static void test_lock_unlock(struct kunit *test)
 {
+	struct drm_exec_priv *priv = test->priv;
 	struct drm_gem_object gobj = { };
 	struct drm_exec exec;
 	int ret;
 
-	drm_gem_private_object_init(&dev, &gobj, PAGE_SIZE);
+	drm_gem_private_object_init(priv->drm, &gobj, PAGE_SIZE);
 
 	drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT);
 	drm_exec_until_all_locked(&exec) {
@@ -74,11 +100,12 @@ static void test_lock_unlock(struct kunit *test)
 
 static void test_duplicates(struct kunit *test)
 {
+	struct drm_exec_priv *priv = test->priv;
 	struct drm_gem_object gobj = { };
 	struct drm_exec exec;
 	int ret;
 
-	drm_gem_private_object_init(&dev, &gobj, PAGE_SIZE);
+	drm_gem_private_object_init(priv->drm, &gobj, PAGE_SIZE);
 
 	drm_exec_init(&exec, DRM_EXEC_IGNORE_DUPLICATES);
 	drm_exec_until_all_locked(&exec) {
@@ -102,11 +129,12 @@ static void test_duplicates(struct kunit *test)
 
 static void test_prepare(struct kunit *test)
 {
+	struct drm_exec_priv *priv = test->priv;
 	struct drm_gem_object gobj = { };
 	struct drm_exec exec;
 	int ret;
 
-	drm_gem_private_object_init(&dev, &gobj, PAGE_SIZE);
+	drm_gem_private_object_init(priv->drm, &gobj, PAGE_SIZE);
 
 	drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT);
 	drm_exec_until_all_locked(&exec) {
@@ -121,14 +149,15 @@ static void test_prepare(struct kunit *test)
 
 static void test_prepare_array(struct kunit *test)
 {
+	struct drm_exec_priv *priv = test->priv;
 	struct drm_gem_object gobj1 = { };
 	struct drm_gem_object gobj2 = { };
 	struct drm_gem_object *array[] = { &gobj1, &gobj2 };
 	struct drm_exec exec;
 	int ret;
 
-	drm_gem_private_object_init(&dev, &gobj1, PAGE_SIZE);
-	drm_gem_private_object_init(&dev, &gobj2, PAGE_SIZE);
+	drm_gem_private_object_init(priv->drm, &gobj1, PAGE_SIZE);
+	drm_gem_private_object_init(priv->drm, &gobj2, PAGE_SIZE);
 
 	drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT);
 	drm_exec_until_all_locked(&exec)
@@ -150,6 +179,7 @@ static struct kunit_case drm_exec_tests[] = {
 
 static struct kunit_suite drm_exec_test_suite = {
 	.name = "drm_exec",
+	.init = drm_exec_test_init,
 	.test_cases = drm_exec_tests,
 };