Re: [PATCH] drm/amd/display: Fix use-after-free bugs in KUnit tests

On 7/24/26 12:37, Alex Hung wrote:
> Reviewed-by: Alex Hung <[email protected]>
>
> With two comments:
> 1. There is a minor conflicts on include
> 2. The following code seems to have the same patterns (passing to 
> drmm_* functions). Do they need to be changed too?
None of those functions exist in my tree. Which might also explain the 
include conflict. I'm using drm-tip fetched the same day I posted the 
patch. Should I be basing the patch on a different tree?

John.


>
>
> --- 
> drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c
> +++ 
> drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c
> @@ -3645,7 +3645,7 @@ static struct dm_test_stream_ctx 
> *dm_test_stream_ctx_alloc(struct kunit *test)
> DRIVER_MODESET);
>         KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx->drm);
>
> -       ctx->aconnector = kunit_kzalloc(test, 
> sizeof(*ctx->aconnector), GFP_KERNEL);
> +       ctx->aconnector = drmm_kzalloc(ctx->drm, 
> sizeof(*ctx->aconnector), GFP_KERNEL);
>         KUNIT_ASSERT_NOT_NULL(test, ctx->aconnector);
>         KUNIT_ASSERT_EQ(test,
>                 drmm_connector_init(ctx->drm, &ctx->aconnector->base,
> @@ -3903,7 +3903,7 @@ static void 
> dm_test_poll_dac_load_returns_cached(struct kunit *test)
>         KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
>         adev = drm_to_adev(drm);
>
> -       aconnector = kunit_kzalloc(test, sizeof(*aconnector), 
> GFP_KERNEL);
> +       aconnector = drmm_kzalloc(drm, sizeof(*aconnector), GFP_KERNEL);
>         KUNIT_ASSERT_NOT_NULL(test, aconnector);
>         KUNIT_ASSERT_EQ(test,
>                 drmm_connector_init(drm, &aconnector->base,
> @@ -3950,7 +3950,7 @@ static struct amdgpu_dm_connector 
> *dm_test_reg_connector(struct kunit *test)
>                                                   DRIVER_MODESET);
>         KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
>
> -       aconnector = kunit_kzalloc(test, sizeof(*aconnector), 
> GFP_KERNEL);
> +       aconnector = drmm_kzalloc(drm, sizeof(*aconnector), GFP_KERNEL);
>         KUNIT_ASSERT_NOT_NULL(test, aconnector);
>         KUNIT_ASSERT_EQ(test,
>                 drmm_connector_init(drm, &aconnector->base,
> @@ -4405,7 +4405,7 @@ dm_test_modes_ctx_alloc(struct kunit *test, int 
> connector_type)
>         ctx->drm = dm_test_alloc_drm(test);
>         ctx->aconnector = dm_test_add_connector(test, ctx->drm, 
> connector_type);
>
> -       ctx->aenc = kunit_kzalloc(test, sizeof(*ctx->aenc), GFP_KERNEL);
> +       ctx->aenc = drmm_kzalloc(ctx->drm, sizeof(*ctx->aenc), 
> GFP_KERNEL);
>         KUNIT_ASSERT_NOT_NULL(test, ctx->aenc);
>         KUNIT_ASSERT_EQ(test,
>                         drmm_encoder_init(ctx->drm, &ctx->aenc->base, 
> NULL,
>
>
> On 7/23/26 17:35, John Harrison wrote:
>> When running the KUnit tests with memory debugging enabled, a bunch of
>> use-after-free errors are hit. These are due to using KUnit managed
>> memory for the test objects but then giving them over to DRM managed
>> objects. The KUnit stuff is deallocated first and when the DRM side
>> calls its clean up helpers, it hits memory that has been freed already.
>>
>> NB: There is still a use-after-free bug in the writeback tests.
>> However, fixing that requires driver side changes as well as test side
>> changes. Those changes are part of:
>>    https://patchwork.freedesktop.org/series/152420/
>>
>> Signed-off-by: John Harrison <[email protected]>
>> CC: Alex Hung <[email protected]>
>> CC: Harry Wentland <[email protected]>
>> ---
>>   .../tests/amdgpu_dm_connector_test.c          | 37 ++++++++++---------
>>   .../amdgpu_dm/tests/amdgpu_dm_kunit_helpers.c |  3 +-
>>   .../amdgpu_dm/tests/amdgpu_dm_wb_test.c       |  5 ++-
>>   3 files changed, 24 insertions(+), 21 deletions(-)
>>
>> diff --git 
>> a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c 
>> b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c
>> index 0a5d439f66c3..93a854d4fdfa 100644
>> --- 
>> a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c
>> +++ 
>> b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_connector_test.c
>> @@ -12,6 +12,7 @@
>>   #include <drm/drm_crtc.h>
>>   #include <drm/drm_edid.h>
>>   #include <drm/drm_kunit_helpers.h>
>> +#include <drm/drm_managed.h>
>>   #include <drm/drm_mode_object.h>
>>   #include <drm/drm_property.h>
>>   #include <linux/hdmi.h>
>> @@ -1449,7 +1450,7 @@ static void 
>> dm_test_funcs_reset_sets_defaults(struct kunit *test)
>>                              DRIVER_MODESET);
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
>>   -    connector = kunit_kzalloc(test, sizeof(*connector), GFP_KERNEL);
>> +    connector = drmm_kzalloc(drm, sizeof(*connector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, connector);
>>         drmm_connector_init(drm, connector, &dm_test_connector_funcs,
>> @@ -1488,7 +1489,7 @@ static void 
>> dm_test_funcs_reset_edp_abm_level(struct kunit *test)
>>                              DRIVER_MODESET);
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
>>   -    connector = kunit_kzalloc(test, sizeof(*connector), GFP_KERNEL);
>> +    connector = drmm_kzalloc(drm, sizeof(*connector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, connector);
>>         drmm_connector_init(drm, connector, &dm_test_connector_funcs,
>> @@ -1526,7 +1527,7 @@ static void 
>> dm_test_funcs_reset_edp_abm_disabled(struct kunit *test)
>>                              DRIVER_MODESET);
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
>>   -    connector = kunit_kzalloc(test, sizeof(*connector), GFP_KERNEL);
>> +    connector = drmm_kzalloc(drm, sizeof(*connector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, connector);
>>         drmm_connector_init(drm, connector, &dm_test_connector_funcs,
>> @@ -1568,7 +1569,7 @@ static void 
>> dm_test_atomic_dup_state_copies_fields(struct kunit *test)
>>                              DRIVER_MODESET);
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
>>   -    connector = kunit_kzalloc(test, sizeof(*connector), GFP_KERNEL);
>> +    connector = drmm_kzalloc(drm, sizeof(*connector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, connector);
>>         drmm_connector_init(drm, connector, &dm_test_connector_funcs,
>> @@ -2359,8 +2360,8 @@ static void setup_panel_type_fixture(struct 
>> kunit *test,
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fixture->drm);
>>       fixture->adev = drm_to_adev(fixture->drm);
>>   -    fixture->aconnector = kunit_kzalloc(test, 
>> sizeof(*fixture->aconnector),
>> -                        GFP_KERNEL);
>> +    fixture->aconnector = drmm_kzalloc(fixture->drm, 
>> sizeof(*fixture->aconnector),
>> +                       GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fixture->aconnector);
>>       fixture->link = kunit_kzalloc(test, sizeof(*fixture->link), 
>> GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fixture->link);
>> @@ -2554,9 +2555,9 @@ static void 
>> dm_test_update_subconnector_dp_with_sink(struct kunit *test)
>>                              DRIVER_MODESET);
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
>>   -    aconnector = kunit_kzalloc(test, sizeof(*aconnector), 
>> GFP_KERNEL);
>> +    aconnector = drmm_kzalloc(drm, sizeof(*aconnector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, aconnector);
>> -    link = kunit_kzalloc(test, sizeof(*link), GFP_KERNEL);
>> +    link = drmm_kzalloc(drm, sizeof(*link), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, link);
>>         drmm_connector_init(drm, &aconnector->base, 
>> &dm_test_connector_funcs,
>> @@ -2598,9 +2599,9 @@ static void 
>> dm_test_update_subconnector_dp_no_sink(struct kunit *test)
>>                              DRIVER_MODESET);
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
>>   -    aconnector = kunit_kzalloc(test, sizeof(*aconnector), 
>> GFP_KERNEL);
>> +    aconnector = drmm_kzalloc(drm, sizeof(*aconnector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, aconnector);
>> -    link = kunit_kzalloc(test, sizeof(*link), GFP_KERNEL);
>> +    link = drmm_kzalloc(drm, sizeof(*link), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, link);
>>         drmm_connector_init(drm, &aconnector->base, 
>> &dm_test_connector_funcs,
>> @@ -2641,9 +2642,9 @@ static void 
>> dm_test_update_subconnector_non_dp_noop(struct kunit *test)
>>                              DRIVER_MODESET);
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
>>   -    aconnector = kunit_kzalloc(test, sizeof(*aconnector), 
>> GFP_KERNEL);
>> +    aconnector = drmm_kzalloc(drm, sizeof(*aconnector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, aconnector);
>> -    link = kunit_kzalloc(test, sizeof(*link), GFP_KERNEL);
>> +    link = drmm_kzalloc(drm, sizeof(*link), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, link);
>>         drmm_connector_init(drm, &aconnector->base, 
>> &dm_test_connector_funcs,
>> @@ -2657,7 +2658,7 @@ static void 
>> dm_test_update_subconnector_non_dp_noop(struct kunit *test)
>>         link->dpcd_caps.dongle_type = DISPLAY_DONGLE_DP_HDMI_CONVERTER;
>>       aconnector->dc_link = link;
>> -    aconnector->dc_sink = kunit_kzalloc(test, 
>> sizeof(*aconnector->dc_sink), GFP_KERNEL);
>> +    aconnector->dc_sink = drmm_kzalloc(drm, 
>> sizeof(*aconnector->dc_sink), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, aconnector->dc_sink);
>>         update_subconnector_property(aconnector);
>> @@ -2804,7 +2805,7 @@ static struct amdgpu_dm_connector 
>> *dm_test_add_connector(struct kunit *test,
>>   {
>>       struct amdgpu_dm_connector *aconnector;
>>   -    aconnector = kunit_kzalloc(test, sizeof(*aconnector), 
>> GFP_KERNEL);
>> +    aconnector = drmm_kzalloc(drm, sizeof(*aconnector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, aconnector);
>>         KUNIT_ASSERT_EQ(test,
>> @@ -3103,7 +3104,7 @@ static struct dm_test_panel_ctx 
>> *dm_test_panel_ctx_alloc(struct kunit *test)
>>       KUNIT_ASSERT_NOT_NULL(test, prop);
>>       ctx->drm->mode_config.panel_type_property = prop;
>>   -    ctx->aconnector = kunit_kzalloc(test, 
>> sizeof(*ctx->aconnector), GFP_KERNEL);
>> +    ctx->aconnector = drmm_kzalloc(ctx->drm, 
>> sizeof(*ctx->aconnector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, ctx->aconnector);
>>       KUNIT_ASSERT_EQ(test,
>>           drmm_connector_init(ctx->drm, &ctx->aconnector->base,
>> @@ -3112,7 +3113,7 @@ static struct dm_test_panel_ctx 
>> *dm_test_panel_ctx_alloc(struct kunit *test)
>> drm_object_attach_property(&ctx->aconnector->base.base, prop,
>>                      DRM_MODE_PANEL_TYPE_UNKNOWN);
>>   -    ctx->link = kunit_kzalloc(test, sizeof(*ctx->link), GFP_KERNEL);
>> +    ctx->link = drmm_kzalloc(ctx->drm, sizeof(*ctx->link), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, ctx->link);
>>       ctx->aconnector->dc_link = ctx->link;
>>   @@ -3376,14 +3377,14 @@ static struct dm_test_fill_ctx 
>> *dm_test_fill_ctx_alloc(struct kunit *test)
>>                                  DRIVER_MODESET);
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx->drm);
>>   -    ctx->aconnector = kunit_kzalloc(test, 
>> sizeof(*ctx->aconnector), GFP_KERNEL);
>> +    ctx->aconnector = drmm_kzalloc(ctx->drm, 
>> sizeof(*ctx->aconnector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, ctx->aconnector);
>>       KUNIT_ASSERT_EQ(test,
>>           drmm_connector_init(ctx->drm, &ctx->aconnector->base,
>>                       &dm_test_connector_funcs,
>>                       DRM_MODE_CONNECTOR_DisplayPort, NULL), 0);
>>   -    ctx->conn_state = kunit_kzalloc(test, 
>> sizeof(*ctx->conn_state), GFP_KERNEL);
>> +    ctx->conn_state = drmm_kzalloc(ctx->drm, 
>> sizeof(*ctx->conn_state), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, ctx->conn_state);
>>       ctx->stream = kunit_kzalloc(test, sizeof(*ctx->stream), 
>> GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, ctx->stream);
>> diff --git 
>> a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_kunit_helpers.c 
>> b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_kunit_helpers.c
>> index 58615cdbe854..7d5e3823b33b 100644
>> --- 
>> a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_kunit_helpers.c
>> +++ 
>> b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_kunit_helpers.c
>> @@ -8,6 +8,7 @@
>>   #include <kunit/test.h>
>>   #include <linux/module.h>
>>   #include <drm/drm_kunit_helpers.h>
>> +#include <drm/drm_managed.h>
>>     #include "dc.h"
>>   #include "core_types.h"
>> @@ -127,7 +128,7 @@ struct amdgpu_dm_connector 
>> *dm_kunit_alloc_connector(struct kunit *test,
>>   {
>>       struct amdgpu_dm_connector *aconnector;
>>   -    aconnector = kunit_kzalloc(test, sizeof(*aconnector), 
>> GFP_KERNEL);
>> +    aconnector = drmm_kzalloc(adev_to_drm(adev), 
>> sizeof(*aconnector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, aconnector);
>>         if (adev)
>> diff --git 
>> a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_wb_test.c 
>> b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_wb_test.c
>> index b43bc244487e..3454cf371414 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_wb_test.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_wb_test.c
>> @@ -12,6 +12,7 @@
>>   #include <drm/drm_fourcc.h>
>>   #include <drm/drm_framebuffer.h>
>>   #include <drm/drm_kunit_helpers.h>
>> +#include <drm/drm_managed.h>
>>   #include <drm/drm_mode.h>
>>   #include <drm/drm_modes.h>
>>   #include <drm/drm_writeback.h>
>> @@ -266,7 +267,7 @@ static void 
>> dm_test_wb_get_modes_returns_modes(struct kunit *test)
>>                              DRIVER_MODESET | DRIVER_ATOMIC);
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
>>   -    connector = kunit_kzalloc(test, sizeof(*connector), GFP_KERNEL);
>> +    connector = drmm_kzalloc(drm, sizeof(*connector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, connector);
>>         drmm_connector_init(drm, connector, &dm_wb_test_connector_funcs,
>> @@ -301,7 +302,7 @@ static void 
>> dm_test_wb_get_modes_bounded_by_max(struct kunit *test)
>>                              DRIVER_MODESET | DRIVER_ATOMIC);
>>       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
>>   -    connector = kunit_kzalloc(test, sizeof(*connector), GFP_KERNEL);
>> +    connector = drmm_kzalloc(drm, sizeof(*connector), GFP_KERNEL);
>>       KUNIT_ASSERT_NOT_NULL(test, connector);
>>         drmm_connector_init(drm, connector, &dm_wb_test_connector_funcs,
>