Re: [PATCH v7 4/5] drm: Suppress intentional warning backtraces in scaling unit tests

[David Gow]

Le 20/04/2026 à 8:28 PM, Albert Esteve a écrit :
From: Guenter Roeck <li...@roeck-us.net>
The drm_test_rect_calc_hscale and drm_test_rect_calc_vscale unit tests
intentionally trigger warning backtraces by providing bad parameters to
the tested functions. What is tested is the return value, not the existence
of a warning backtrace. Suppress the backtraces to avoid clogging the
kernel log and distraction from real problems.

Tested-by: Linux Kernel Functional Testing <l...@linaro.org>
Acked-by: Dan Carpenter <dan.carpen...@linaro.org>
Acked-by: Maíra Canal <mca...@igalia.com>
Cc: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
Cc: David Airlie <airl...@gmail.com>
Cc: Daniel Vetter <dan...@ffwll.ch>
Signed-off-by: Guenter Roeck <li...@roeck-us.net>
Signed-off-by: Alessandro Carminati <acarm...@redhat.com>
Signed-off-by: Albert Esteve <aest...@redhat.com>
---

Acked-by: David Gow <da...@davidgow.net>

Some of the suggestions in the thread around __cleanup() et al. sound 
good to me, too. I suspect that it should work given the 
kunit_add_action() / resource system use anyway, so even if an assertion 
fires, things should be cleaned up properly.

Cheers,
-- David

  drivers/gpu/drm/tests/drm_rect_test.c | 14 ++++++++++++++
  1 file changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/tests/drm_rect_test.c 
b/drivers/gpu/drm/tests/drm_rect_test.c
index 17e1f34b76101..1dd7d819165e7 100644
--- a/drivers/gpu/drm/tests/drm_rect_test.c
+++ b/drivers/gpu/drm/tests/drm_rect_test.c
@@ -409,8 +409,15 @@ static void drm_test_rect_calc_hscale(struct kunit *test)
        const struct drm_rect_scale_case *params = test->param_value;
        int scaling_factor;
  
+	/*
+        * drm_rect_calc_hscale() generates a warning backtrace whenever bad
+        * parameters are passed to it. This affects all unit tests with an
+        * error code in expected_scaling_factor.
+        */
+       KUNIT_START_SUPPRESSED_WARNING(test);
        scaling_factor = drm_rect_calc_hscale(&params->src, &params->dst,
                                              params->min_range, 
params->max_range);
+       KUNIT_END_SUPPRESSED_WARNING(test);
  
  	KUNIT_EXPECT_EQ(test, scaling_factor, params->expected_scaling_factor);
  }
@@ -420,8 +427,15 @@ static void drm_test_rect_calc_vscale(struct kunit *test)
        const struct drm_rect_scale_case *params = test->param_value;
        int scaling_factor;
  
+	/*
+        * drm_rect_calc_vscale() generates a warning backtrace whenever bad
+        * parameters are passed to it. This affects all unit tests with an
+        * error code in expected_scaling_factor.
+        */
+       KUNIT_START_SUPPRESSED_WARNING(test);
        scaling_factor = drm_rect_calc_vscale(&params->src, &params->dst,
                                              params->min_range, 
params->max_range);
+       KUNIT_END_SUPPRESSED_WARNING(test);
  
  	KUNIT_EXPECT_EQ(test, scaling_factor, params->expected_scaling_factor);
  }