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Tue, 30 Dec 2025 21:51:15 -0800 (PST) From: Shenghao Yang To: Ruben Wauters , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Shenghao Yang , stable@vger.kernel.org Subject: [PATCH] drm/gud: fix NULL fb and crtc dereferences on USB disconnect Date: Wed, 31 Dec 2025 13:50:26 +0800 Message-ID: <20251231055039.44266-1-me@shenghaoyang.info> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" On disconnect drm_atomic_helper_disable_all() is called which sets both the fb and crtc for a plane to NULL before invoking a commit. This causes a kernel oops on every display disconnect. Add guards for those dereferences. Cc: # 6.18.x Signed-off-by: Shenghao Yang Reviewed-by: Ruben Wauters --- drivers/gpu/drm/gud/gud_pipe.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c index 76d77a736d84..4b77be94348d 100644 --- a/drivers/gpu/drm/gud/gud_pipe.c +++ b/drivers/gpu/drm/gud/gud_pipe.c @@ -457,27 +457,20 @@ int gud_plane_atomic_check(struct drm_plane *plane, 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_crtc *crtc =3D new_plane_state->crtc; - struct drm_crtc_state *crtc_state; + struct drm_crtc_state *crtc_state =3D NULL; const struct drm_display_mode *mode; struct drm_framebuffer *old_fb =3D old_plane_state->fb; struct drm_connector_state *connector_state =3D NULL; struct drm_framebuffer *fb =3D new_plane_state->fb; - const struct drm_format_info *format =3D fb->format; + const struct drm_format_info *format; struct drm_connector *connector; unsigned int i, num_properties; struct gud_state_req *req; int idx, ret; size_t len; =20 - if (drm_WARN_ON_ONCE(plane->dev, !fb)) - return -EINVAL; - - if (drm_WARN_ON_ONCE(plane->dev, !crtc)) - return -EINVAL; - - crtc_state =3D drm_atomic_get_new_crtc_state(state, crtc); - - mode =3D &crtc_state->mode; + if (crtc) + crtc_state =3D drm_atomic_get_new_crtc_state(state, crtc); =20 ret =3D drm_atomic_helper_check_plane_state(new_plane_state, crtc_state, DRM_PLANE_NO_SCALING, @@ -492,6 +485,9 @@ int gud_plane_atomic_check(struct drm_plane *plane, if (old_plane_state->rotation !=3D new_plane_state->rotation) crtc_state->mode_changed =3D true; =20 + mode =3D &crtc_state->mode; + format =3D fb->format; + if (old_fb && old_fb->format !=3D format) crtc_state->mode_changed =3D true; =20 @@ -598,7 +594,7 @@ void gud_plane_atomic_update(struct drm_plane *plane, struct drm_atomic_helper_damage_iter iter; int ret, idx; =20 - if (crtc->state->mode_changed || !crtc->state->enable) { + if (!crtc || crtc->state->mode_changed || !crtc->state->enable) { cancel_work_sync(&gdrm->work); mutex_lock(&gdrm->damage_lock); if (gdrm->fb) { --=20 2.52.0