drm/tegra: hub: Fix dereference before check

[ Upstream commit 7cf77b273a8fc51e7de622fa6691abd4436a9a6b ]

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org>

diff --git a/drivers/gpu/drm/tegra/hub.c b/drivers/gpu/drm/tegra/hub.c
index 8f4fcbb515fb4d16e27ed89f378993c214577efe..bb97cad1eb699007f6457d7cabac3ea78d576653 100644 (file)
--- a/drivers/gpu/drm/tegra/hub.c
+++ b/drivers/gpu/drm/tegra/hub.c
@@ -378,14 +378,16 @@ static int tegra_shared_plane_atomic_check(struct drm_plane *plane,
 static void tegra_shared_plane_atomic_disable(struct drm_plane *plane,
                                              struct drm_plane_state *old_state)
 {
-       struct tegra_dc *dc = to_tegra_dc(old_state->crtc);
        struct tegra_plane *p = to_tegra_plane(plane);
+       struct tegra_dc *dc;
        u32 value;
 
        /* rien ne va plus */
        if (!old_state || !old_state->crtc)
                return;
 
+       dc = to_tegra_dc(old_state->crtc);
+
        /*
         * XXX Legacy helpers seem to sometimes call ->atomic_disable() even
         * on planes that are already disabled. Make sure we fallback to the