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From:   Andrey Shumilin <shum.sdl@nppct.ru>
To:     Karol Herbst <kherbst@redhat.com>
Cc:     Andrey Shumilin <shum.sdl@nppct.ru>, Lyude Paul <lyude@redhat.com>,
        Danilo Krummrich <dakr@redhat.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>,
        Jani Nikula <jani.nikula@intel.com>,
        dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, khoroshilov@ispras.ru,
        ykarpov@ispras.ru, vmerzlyakov@ispras.ru, vefanov@ispras.ru
Subject: [PATCH] tvnv17.c: Adding a NULL pointer check.
Date:   Thu, 16 Nov 2023 09:51:59 +0300
Message-Id: <20231116065159.37876-1-shum.sdl@nppct.ru>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

It is possible to dereference a null pointer if drm_mode_duplicate() returns NULL.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Andrey Shumilin <shum.sdl@nppct.ru>
---
 drivers/gpu/drm/nouveau/dispnv04/tvnv17.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
index 670c9739e5e1..1f0c5f4a5fd2 100644
--- a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
+++ b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
@@ -209,7 +209,8 @@ static int nv17_tv_get_ld_modes(struct drm_encoder *encoder,
 		struct drm_display_mode *mode;
 
 		mode = drm_mode_duplicate(encoder->dev, tv_mode);
-
+		if (mode == NULL)
+			continue;
 		mode->clock = tv_norm->tv_enc_mode.vrefresh *
 			mode->htotal / 1000 *
 			mode->vtotal / 1000;
@@ -258,6 +259,8 @@ 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 == NULL)
+				continue;
 			mode->type |= DRM_MODE_TYPE_PREFERRED;
 
 		} else {
-- 
2.30.2