diff options
| author | Thomas Zimmermann <tzimmermann@suse.de> | 2025-07-15 17:58:11 +0200 |
|---|---|---|
| committer | Thomas Zimmermann <tzimmermann@suse.de> | 2025-07-17 12:26:19 +0200 |
| commit | 0ecfb8ddb953605cadd806de5b62e632c8e0e49e (patch) | |
| tree | 5e2d3e57cade4d6de23aab7d8d4a5f0fb322a41e | |
| parent | 15f77764e90a713ee3916ca424757688e4f565b9 (diff) | |
Revert "drm/virtio: Use dma_buf from GEM object instance"
This reverts commit 415cb45895f43015515473fbc40563ca5eec9a7c.
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/20250715155934.150656-3-tzimmermann@suse.de
| -rw-r--r-- | drivers/gpu/drm/virtio/virtgpu_prime.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c b/drivers/gpu/drm/virtio/virtgpu_prime.c index 1118a0250279..ce49282198cb 100644 --- a/drivers/gpu/drm/virtio/virtgpu_prime.c +++ b/drivers/gpu/drm/virtio/virtgpu_prime.c @@ -204,15 +204,16 @@ static void virtgpu_dma_buf_free_obj(struct drm_gem_object *obj) { struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj); struct virtio_gpu_device *vgdev = obj->dev->dev_private; + struct dma_buf_attachment *attach = obj->import_attach; if (drm_gem_is_imported(obj)) { - struct dma_buf *dmabuf = obj->dma_buf; + struct dma_buf *dmabuf = attach->dmabuf; dma_resv_lock(dmabuf->resv, NULL); virtgpu_dma_buf_unmap(bo); dma_resv_unlock(dmabuf->resv); - dma_buf_detach(dmabuf, obj->import_attach); + dma_buf_detach(dmabuf, attach); dma_buf_put(dmabuf); } |