drm/sched: Fix a race in DRM_GPU_SCHED_STAT_NO_HANG test

The "skip reset" test waits for the timeout handler to run for the duration of 2 * MOCK_TIMEOUT, and because the mock scheduler opted to remove the "skip reset" flag once it fires, this gives opportunity for the timeout handler to run twice. Second time the job will be removed from the mock scheduler job list and the drm_mock_sched_advance() call in the test will fail. Fix it by making the "don't reset" flag persist for the lifetime of the job and add a new flag to verify that the code path had executed as expected.

Tvrtko Ursulin committed 1 year ago

Commit 2650bc41 parent 28c5c483 files · +7 −6Browse files

Unified · Split

3 files

drivers/gpu/drm/scheduler/tests/mock_scheduler.c +1 −1
drivers/gpu/drm/scheduler/tests/sched_tests.h +4 −3
drivers/gpu/drm/scheduler/tests/tests_basic.c +2 −2

drivers/gpu/drm/scheduler/tests/mock_scheduler.c+1−1

@@ -219,7 +219,7 @@ mock_sched_timedout_job(struct drm_sched_job *sched_job) · 218 unmodified lines
219	219	unsigned long flags;
220	220
221	221	if (job->flags & DRM_MOCK_SCHED_JOB_DONT_RESET) {
222		− job->flags &= ~DRM_MOCK_SCHED_JOB_DONT_RESET;
	222	+ job->flags \|= DRM_MOCK_SCHED_JOB_RESET_SKIPPED;
223	223	return DRM_GPU_SCHED_STAT_NO_HANG;
224	224	}
225	225

drivers/gpu/drm/scheduler/tests/sched_tests.h+4−3

@@ -95,9 +95,10 @@ struct drm_mock_sched_job { · 94 unmodified lines
95	95
96	96	struct completion done;
97	97
98		−#define DRM_MOCK_SCHED_JOB_DONE 0x1
99		−#define DRM_MOCK_SCHED_JOB_TIMEDOUT 0x2
100		−#define DRM_MOCK_SCHED_JOB_DONT_RESET 0x4
	98	+#define DRM_MOCK_SCHED_JOB_DONE 0x1
	99	+#define DRM_MOCK_SCHED_JOB_TIMEDOUT 0x2
	100	+#define DRM_MOCK_SCHED_JOB_DONT_RESET 0x4
	101	+#define DRM_MOCK_SCHED_JOB_RESET_SKIPPED 0x8
101	102	unsigned long flags;
102	103
103	104	struct list_head link;

drivers/gpu/drm/scheduler/tests/tests_basic.c+2−2

@@ -317,8 +317,8 @@ static void drm_sched_skip_reset(struct kunit *test) · 316 unmodified lines
317	317	KUNIT_ASSERT_FALSE(test, done);
318	318
319	319	KUNIT_ASSERT_EQ(test,
320		− job->flags & DRM_MOCK_SCHED_JOB_DONT_RESET,
321		− 0);
	320	+ job->flags & DRM_MOCK_SCHED_JOB_RESET_SKIPPED,
	321	+ DRM_MOCK_SCHED_JOB_RESET_SKIPPED);
322	322
323	323	i = drm_mock_sched_advance(sched, 1);
324	324	KUNIT_ASSERT_EQ(test, i, 1);