drm: zynqmp_kms: Unplug DRM device before removal

Sean Anderson · tomba · commit 2e07c88914fc · 2024-10-30T14:17:33.000+02:00
Prevent userspace accesses to the DRM device from causing use-after-frees by unplugging the device before we remove it. This causes any further userspace accesses to result in an error without further calls into this driver's internals. Fixes: d76271d ("drm: xlnx: DRM/KMS driver for Xilinx ZynqMP DisplayPort Subsystem") Closes: https://lore.kernel.org/dri-devel/4d8f4c9b-2efb-4774-9a37-2f257f79b2c9@linux.dev/ Signed-off-by: Sean Anderson <sean.anderson@linux.dev> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Link: https://patchwork.freedesktop.org/patch/msgid/20240809193600.3360015-2-sean.anderson@linux.dev
diff --git a/drivers/gpu/drm/xlnx/zynqmp_kms.c b/drivers/gpu/drm/xlnx/zynqmp_kms.c
@@ -538,7 +538,7 @@ void zynqmp_dpsub_drm_cleanup(struct zynqmp_dpsub *dpsub)
 {
 	struct drm_device *drm = &dpsub->drm->dev;
 
-	drm_dev_unregister(drm);
+	drm_dev_unplug(drm);
 	drm_atomic_helper_shutdown(drm);
 	drm_encoder_cleanup(&dpsub->drm->encoder);
 	drm_kms_helper_poll_fini(drm);

Original file line number	Diff line number	Diff line change
`@@ -538,7 +538,7 @@ void zynqmp_dpsub_drm_cleanup(struct zynqmp_dpsub *dpsub)`
`538`	`538`	`{`
`539`	`539`	`struct drm_device *drm = &dpsub->drm->dev;`
`540`	`540`
`541`		`- drm_dev_unregister(drm);`
	`541`	`+ drm_dev_unplug(drm);`
`542`	`542`	`drm_atomic_helper_shutdown(drm);`
`543`	`543`	`drm_encoder_cleanup(&dpsub->drm->encoder);`
`544`	`544`	`drm_kms_helper_poll_fini(drm);`