[PATCH] drm/ast: potential dereference of null pointer

[Jiasheng Jiang]

he return value of kzalloc() needs to be checked.
To avoid use of null pointer '&ast_state->base' in case of the
failure of alloc.

Fixes: f0adbc382b8b ("drm/ast: Allocate initial CRTC state of the correct size")
Signed-off-by: Jiasheng Jiang <jiash...@iscas.ac.cn>
---
 drivers/gpu/drm/ast/ast_mode.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index 36d9575aa27b..67f8e3f90ea2 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -1120,7 +1120,8 @@ static void ast_crtc_reset(struct drm_crtc *crtc)
        if (crtc->state)
                crtc->funcs->atomic_destroy_state(crtc, crtc->state);
 
-       __drm_atomic_helper_crtc_reset(crtc, &ast_state->base);
+       if (ast_state)
+               __drm_atomic_helper_crtc_reset(crtc, &ast_state->base);
 }
 
 static struct drm_crtc_state *
-- 
2.25.1