drm/exynos: dpi: Fix NULL pointer dereference with legacy bindings

If there is no panel node in DT and instead display timings are provided
directly in FIMD node, there is no panel object created and ctx->panel
becomes NULL. However during Exynos DRM initialization
drm_helper_hpd_irq_event() is called, which in turns calls
exynos_dpi_detect(), which dereferences ctx->panel without a check,
causing a NULL pointer derefrence.

This patch fixes the issue by adding necessary NULL pointer check.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Reviewed-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dpi.c b/drivers/gpu/drm/exynos/exynos_drm_dpi.c
index 482127f633c573fe84db8faffbe7cf5210df7ac3..9e530f205ad2244f13fdea07e6ec1b322f94550a 100644 (file)
--- a/drivers/gpu/drm/exynos/exynos_drm_dpi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dpi.c
@@ -40,7 +40,7 @@ exynos_dpi_detect(struct drm_connector *connector, bool force)
 {
        struct exynos_dpi *ctx = connector_to_dpi(connector);
 
-       if (!ctx->panel->connector)
+       if (ctx->panel && !ctx->panel->connector)
                drm_panel_attach(ctx->panel, &ctx->connector);
 
        return connector_status_connected;