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Wed, 30 Jul 2025 06:35:31 -0700 (PDT) Received: from localhost ([87.254.0.133]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-3b78d45d010sm7204560f8f.8.2025.07.30.06.35.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 30 Jul 2025 06:35:31 -0700 (PDT) From: Colin Ian King To: Anitha Chrisanthus , Edmund Dea , David Airlie , Simona Vetter , Laurent Pinchart , Thomas Zimmermann , Maxime Ripard , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , dri-devel@lists.freedesktop.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH][next] drm/kmb: Fix dereference of pointer plane before a null check Date: Wed, 30 Jul 2025 14:34:57 +0100 Message-ID: <20250730133457.2076784-1-colin.i.king@gmail.com> X-Mailer: git-send-email 2.50.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Currently pointer plane is being dereferenced on the calls to drm_atomic_get_old_plane_state and drm_atomic_get_new_plane_state when assigning old_plane_state and new_plane_state, this could lead to a null pointer dereference. Fix this by first performing a null pointer check on plane, then assigning old_plane_state and new_plance_state and then null pointer checking these. Fixes: 977697e20b3d ("drm/atomic: Pass the full state to planes atomic disa= ble and update") Fixes: 37418bf14c13 ("drm: Use state helper instead of the plane state poin= ter") Signed-off-by: Colin Ian King --- drivers/gpu/drm/kmb/kmb_plane.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/kmb/kmb_plane.c b/drivers/gpu/drm/kmb/kmb_plan= e.c index 9e0562aa2bcb..07498deba1b6 100644 --- a/drivers/gpu/drm/kmb/kmb_plane.c +++ b/drivers/gpu/drm/kmb/kmb_plane.c @@ -341,10 +341,8 @@ static void kmb_plane_set_alpha(struct kmb_drm_private= *kmb, static void kmb_plane_atomic_update(struct drm_plane *plane, struct drm_atomic_state *state) { - struct drm_plane_state *old_plane_state =3D drm_atomic_get_old_plane_stat= e(state, - plane); - struct drm_plane_state *new_plane_state =3D drm_atomic_get_new_plane_stat= e(state, - plane); + struct drm_plane_state *old_plane_state; + struct drm_plane_state *new_plane_state; struct drm_framebuffer *fb; struct kmb_drm_private *kmb; unsigned int width; @@ -359,7 +357,12 @@ static void kmb_plane_atomic_update(struct drm_plane *= plane, static dma_addr_t addr[MAX_SUB_PLANES]; struct disp_cfg *init_disp_cfg; =20 - if (!plane || !new_plane_state || !old_plane_state) + if (!plane) + return; + + old_plane_state =3D drm_atomic_get_old_plane_state(state, plane); + new_plane_state =3D drm_atomic_get_new_plane_state(state, plane); + if (!old_plane_state || !new_plane_state) return; =20 fb =3D new_plane_state->fb; --=20 2.50.0