[PATCH v9 18/18] drm/virtio: add fence sanity check

From: Gerd Hoffmann
Date: Thu Aug 29 2019 - 06:33:39 EST


Make sure we don't leak half-initialized fences outside the driver.

Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
---
drivers/gpu/drm/virtio/virtgpu_fence.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_fence.c b/drivers/gpu/drm/virtio/virtgpu_fence.c
index a0514f5bd006..a4b9881ca1d3 100644
--- a/drivers/gpu/drm/virtio/virtgpu_fence.c
+++ b/drivers/gpu/drm/virtio/virtgpu_fence.c
@@ -41,6 +41,10 @@ bool virtio_fence_signaled(struct dma_fence *f)
{
struct virtio_gpu_fence *fence = to_virtio_fence(f);

+ if (WARN_ON_ONCE(fence->f.seqno == 0))
+ /* leaked fence outside driver before completing
+ * initialization with virtio_gpu_fence_emit */
+ return false;
if (atomic64_read(&fence->drv->last_seq) >= fence->f.seqno)
return true;
return false;
--
2.18.1