From bb7f4972a6ff9a537b87e1b0ecf0e561f2761dd3 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Tue, 15 Jul 2025 17:58:13 +0200 Subject: [PATCH] Revert "drm/etnaviv: Use dma_buf from GEM object instance" MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This reverts commit e91eb3ae415472b28211d7fed07fa283845b311e. The dma_buf field in struct drm_gem_object is not stable over the object instance's lifetime. The field becomes NULL when user space releases the final GEM handle on the buffer object. This resulted in a NULL-pointer deref. Workarounds in commit 5307dce878d4 ("drm/gem: Acquire references on GEM handles for framebuffers") and commit f6bfc9afc751 ("drm/framebuffer: Acquire internal references on GEM handles") only solved the problem partially. They especially don't work for buffer objects without a DRM framebuffer associated. Hence, this revert to going back to using .import_attach->dmabuf. Signed-off-by: Thomas Zimmermann Reviewed-by: Simona Vetter Acked-by: Christian König Acked-by: Zack Rusin Link: https://lore.kernel.org/r/20250715155934.150656-4-tzimmermann@suse.de --- drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c index 917ad527c9614..40a50c60dfff7 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c @@ -65,7 +65,7 @@ static void etnaviv_gem_prime_release(struct etnaviv_gem_object *etnaviv_obj) struct iosys_map map = IOSYS_MAP_INIT_VADDR(etnaviv_obj->vaddr); if (etnaviv_obj->vaddr) - dma_buf_vunmap_unlocked(etnaviv_obj->base.dma_buf, &map); + dma_buf_vunmap_unlocked(etnaviv_obj->base.import_attach->dmabuf, &map); /* Don't drop the pages for imported dmabuf, as they are not * ours, just free the array we allocated: @@ -82,7 +82,7 @@ static void *etnaviv_gem_prime_vmap_impl(struct etnaviv_gem_object *etnaviv_obj) lockdep_assert_held(&etnaviv_obj->lock); - ret = dma_buf_vmap(etnaviv_obj->base.dma_buf, &map); + ret = dma_buf_vmap(etnaviv_obj->base.import_attach->dmabuf, &map); if (ret) return NULL; return map.vaddr; -- 2.47.2