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From:   Ma Ke <make_ruc2021@163.com>
To:     kherbst@redhat.com, lyude@redhat.com, dakr@redhat.com,
        airlied@gmail.com, daniel@ffwll.ch, tzimmermann@suse.de,
        noralf@tronnes.org, mripard@kernel.org, jani.nikula@intel.com,
        make_ruc2021@163.com
Cc:     dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] drm/nouveau/dispnv04: fix a possible null pointer dereference
Date:   Fri, 13 Oct 2023 09:18:50 +0800
Message-Id: <20231013011850.103967-1-make_ruc2021@163.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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

Signed-off-by: Ma Ke <make_ruc2021@163.com>
---
 drivers/gpu/drm/nouveau/dispnv04/tvnv17.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
index 670c9739e5e1..9c3dc9a5bb46 100644
--- a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
+++ b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
@@ -258,6 +258,8 @@ 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 {
@@ -265,6 +267,8 @@ 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... */
-- 
2.37.2