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

[Christian König]

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 at riseup.net>
> Tested-by: Danilo Krummrich <dakr at redhat.com>
> Acked-by: Danilo Krummrich <dakr at redhat.com>
> Reviewed-by: Maíra Canal <mcanal at igalia.com>

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@riseup.net/
> 	- 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,
>   };
>