]> git.ipfire.org Git - thirdparty/linux.git/commitdiff
Revert "drm/etnaviv: Use dma_buf from GEM object instance"
authorThomas Zimmermann <tzimmermann@suse.de>
Tue, 15 Jul 2025 15:58:13 +0000 (17:58 +0200)
committerThomas Zimmermann <tzimmermann@suse.de>
Thu, 17 Jul 2025 10:26:19 +0000 (12:26 +0200)
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 <tzimmermann@suse.de>
Reviewed-by: Simona Vetter <simona.vetter@ffwll.ch>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Zack Rusin <zack.rusin@broadcom.com>
Link: https://lore.kernel.org/r/20250715155934.150656-4-tzimmermann@suse.de
drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c

index 917ad527c96146ecae993c0355f5485c00ca330a..40a50c60dfff761a5e57a3eb03d42d7fba24c32a 100644 (file)
@@ -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;