On Fri, 12 Dec 2025 17:00:36 +0100 Thomas Zimmermann tzimmermann@suse.de wrote:

Acquire and release the GEM object's reservation lock around calls to the object's purge operation. The tests use drm_gem_shmem_purge_locked(), which led to errors such as show below.

[ 58.709128] WARNING: CPU: 1 PID: 1354 at drivers/gpu/drm/drm_gem_shmem_helper.c:515 drm_gem_shmem_purge_locked+0x51c/0x740

Only export the new helper drm_gem_shmem_purge() for Kunit tests. This is not an interface for regular drivers.

Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Fixes: 954907f7147d ("drm/shmem-helper: Refactor locked/unlocked functions") Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v6.16+

Reviewed-by: Boris Brezillon boris.brezillon@collabora.com

---

drivers/gpu/drm/drm_gem_shmem_helper.c | 15 +++++++++++++++ drivers/gpu/drm/tests/drm_gem_shmem_test.c | 4 +++- include/drm/drm_gem_shmem_helper.h | 1 + 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index 4ffcf6ed46f5..dfc24392cb61 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -939,6 +939,21 @@ int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv) return ret; } EXPORT_SYMBOL_IF_KUNIT(drm_gem_shmem_madvise);

+int drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem) +{

• struct drm_gem_object *obj = &shmem->base;
• int ret;
• ret = dma_resv_lock_interruptible(obj->resv, NULL);
• if (ret)

• return ret;
  

• drm_gem_shmem_purge_locked(shmem);
• dma_resv_unlock(obj->resv);
• return 0;

+} +EXPORT_SYMBOL_IF_KUNIT(drm_gem_shmem_purge); #endif MODULE_DESCRIPTION("DRM SHMEM memory-management helpers"); diff --git a/drivers/gpu/drm/tests/drm_gem_shmem_test.c b/drivers/gpu/drm/tests/drm_gem_shmem_test.c index d639848e3c8e..4b459f21acfd 100644 --- a/drivers/gpu/drm/tests/drm_gem_shmem_test.c +++ b/drivers/gpu/drm/tests/drm_gem_shmem_test.c @@ -340,7 +340,9 @@ static void drm_gem_shmem_test_purge(struct kunit *test) ret = drm_gem_shmem_is_purgeable(shmem); KUNIT_EXPECT_TRUE(test, ret);

• drm_gem_shmem_purge_locked(shmem);

• ret = drm_gem_shmem_purge(shmem);
• KUNIT_ASSERT_EQ(test, ret, 0);
• KUNIT_EXPECT_NULL(test, shmem->pages); KUNIT_EXPECT_NULL(test, shmem->sgt); KUNIT_EXPECT_EQ(test, shmem->madv, -1);

diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h index 3dd93e2df709..8d56970d7eed 100644 --- a/include/drm/drm_gem_shmem_helper.h +++ b/include/drm/drm_gem_shmem_helper.h @@ -311,6 +311,7 @@ struct drm_gem_object *drm_gem_shmem_prime_import_no_map(struct drm_device *dev, int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem, struct iosys_map *map); void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem, struct iosys_map *map); int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv); +int drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem); #endif #endif /* __DRM_GEM_SHMEM_HELPER_H__ */