[PATCH] drm/exynos: fix race condition UAF in exynos_g2d_exec_ioctl
From: Min Li <hidden>
Date: 2023-05-27 08:18:26
Also in:
dri-devel, linux-samsung-soc, lkml
Subsystem:
drm drivers, drm drivers for exynos, the rest · Maintainers:
David Airlie, Simona Vetter, Inki Dae, Seung-Woo Kim, Kyungmin Park, Linus Torvalds
If it is async, runqueue_node is freed in g2d_runqueue_worker on another worker thread. So in extreme cases, if g2d_runqueue_worker runs first, and then executes the following if statement, there will be use-after-free. Signed-off-by: Min Li <redacted> --- drivers/gpu/drm/exynos/exynos_drm_g2d.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_g2d.c b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
index ec784e58da5c..414e585ec7dd 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_g2d.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_g2d.c@@ -1335,7 +1335,7 @@ int exynos_g2d_exec_ioctl(struct drm_device *drm_dev, void *data, /* Let the runqueue know that there is work to do. */ queue_work(g2d->g2d_workq, &g2d->runqueue_work); - if (runqueue_node->async) + if (req->async) goto out; wait_for_completion(&runqueue_node->complete);
--
2.34.1
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