drm/nouveau/dispnv04: fix null pointer dereference in nv17_tv_get_hd_modes

commit 6d411c8ccc0137a612e0044489030a194ff5c843 upstream.

In nv17_tv_get_hd_modes(), the return value of drm_mode_duplicate() is
assigned to mode, which will lead to a possible NULL pointer dereference
on failure of drm_mode_duplicate(). The same applies to drm_cvt_mode().
Add a check to avoid null pointer dereference.

Cc: stable@vger.kernel.org
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240625081029.2619437-1-make24@iscas.ac.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
index 4a08e61f333678c4fc3d954928c4cc33dce7db86..2033214c4b7848cdf55f2def59c4ecea687f649b 100644 (file)
--- a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
+++ b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
@@ -260,6 +260,8 @@ static int nv17_tv_get_hd_modes(struct drm_encoder *encoder,
                if (modes[i].hdisplay == output_mode->hdisplay &&
                    modes[i].vdisplay == output_mode->vdisplay) {
                        mode = drm_mode_duplicate(encoder->dev, output_mode);
+                       if (!mode)
+                               continue;
                        mode->type |= DRM_MODE_TYPE_PREFERRED;
 
                } else {
@@ -267,6 +269,8 @@ static int nv17_tv_get_hd_modes(struct drm_encoder *encoder,
                                            modes[i].vdisplay, 60, false,
                                            (output_mode->flags &
                                             DRM_MODE_FLAG_INTERLACE), false);
+                       if (!mode)
+                               continue;
                }
 
                /* CVT modes are sometimes unsuitable... */