Re: [PATCH v2] drm/tests: Alloc drm_device on drm_exec tests

Christian König <christian.koenig@xxxxxxx> · Thu, 3 Aug 2023 11:55:13 +0200

Am 28.07.23 um 20:34 schrieb Arthur Grillo:
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-ge6303f323b1a #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: e6303f323b1a ("drm: manager to keep track of GPUs VA mappings")
Signed-off-by: Arthur Grillo <arthurgrillo@xxxxxxxxxx>
Tested-by: Danilo Krummrich <dakr@xxxxxxxxxx>
Acked-by: Danilo Krummrich <dakr@xxxxxxxxxx>
Reviewed-by: Maíra Canal <mcanal@xxxxxxxxxx>

Sorry that I didn't replied earlier, just back from vacation.

Since the patch already made it into drm-misc-next it's to late for my 
rb, but just wanted to say thanks for looking into this.

Christian.

---
v1->v2: https://lore.kernel.org/all/20230727192259.237935-1-arthurgrillo@xxxxxxxxxx/
	- s/test_init/drm_exec_test_init/ (Maíra)
	- s/test_exit/drm_exec_test_exit/ (Maíra)
	- Use test->priv intead of global variables (Maíra and Maxime)

---
  drivers/gpu/drm/tests/drm_exec_test.c | 52 +++++++++++++++++++++++----
  1 file changed, 45 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/tests/drm_exec_test.c b/drivers/gpu/drm/tests/drm_exec_test.c
index 727ac267682e..f02a93601203 100644
--- a/drivers/gpu/drm/tests/drm_exec_test.c
+++ b/drivers/gpu/drm/tests/drm_exec_test.c
@@ -12,11 +12,42 @@
  
  #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 drm_exec_test_exit(struct kunit *test)
+{
+	struct drm_exec_priv *priv = test->priv;
+
+	drm_kunit_helper_free_device(test, priv->dev);
+}
  
  static void sanitycheck(struct kunit *test)
  {
@@ -29,11 +60,12 @@ 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 +80,12 @@ 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 +107,12 @@ 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 +136,12 @@ 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 +156,15 @@ 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 +186,8 @@ static struct kunit_case drm_exec_tests[] = {
  
  static struct kunit_suite drm_exec_test_suite = {
  	.name = "drm_exec",
+	.init = drm_exec_test_init,
+	.exit = drm_exec_test_exit,
  	.test_cases = drm_exec_tests,
  };
  







