linux-kernel - [PATCH v6 1/8] drm: zynqmp_kms: Unplug DRM device before removal

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Message-Id: <20240809193600.3360015-2-sean.anderson@linux.dev>
Date: Fri,  9 Aug 2024 15:35:53 -0400
From: Sean Anderson <sean.anderson@...ux.dev>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	dri-devel@...ts.freedesktop.org
Cc: linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	David Airlie <airlied@...il.com>,
	Michal Simek <michal.simek@....com>,
	Daniel Vetter <daniel@...ll.ch>,
	Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
	Sean Anderson <sean.anderson@...ux.dev>
Subject: [PATCH v6 1/8] drm: zynqmp_kms: Unplug DRM device before removal

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: d76271d22694 ("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@...ux.dev>
---
Thanks to Maxime for pointing out the correct function to use here.

Changes in v6:
- New

 drivers/gpu/drm/xlnx/zynqmp_kms.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xlnx/zynqmp_kms.c b/drivers/gpu/drm/xlnx/zynqmp_kms.c
index bd1368df7870..4556af2faa0f 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_kms.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_kms.c
@@ -536,7 +536,7 @@ 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);
-- 
2.35.1.1320.gc452695387.dirty