linux-kernel - [PATCH] drm/panthor: disable async work during unplug

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Message-ID: <20251029111412.924104-1-ketil.johnsen@arm.com>
Date: Wed, 29 Oct 2025 12:14:10 +0100
From: Ketil Johnsen <ketil.johnsen@....com>
To: Boris Brezillon <boris.brezillon@...labora.com>,
	Steven Price <steven.price@....com>,
	Liviu Dudau <liviu.dudau@....com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>
Cc: Ketil Johnsen <ketil.johnsen@....com>,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] drm/panthor: disable async work during unplug

A previous change, "drm/panthor: Fix UAF race between device unplug and
FW event processing", fixes a real issue where new work was unexpectedly
queued after cancellation. This was fixed by a disable instead.

Apply the same disable logic to other device level async work on device
unplug as a precaution.

Signed-off-by: Ketil Johnsen <ketil.johnsen@....com>
---
 drivers/gpu/drm/panthor/panthor_device.c | 2 +-
 drivers/gpu/drm/panthor/panthor_fw.c     | 2 +-
 drivers/gpu/drm/panthor/panthor_sched.c  | 5 ++---
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
index 962a10e00848e..c4ae78545ef03 100644
--- a/drivers/gpu/drm/panthor/panthor_device.c
+++ b/drivers/gpu/drm/panthor/panthor_device.c
@@ -120,7 +120,7 @@ static void panthor_device_reset_cleanup(struct drm_device *ddev, void *data)
 {
 	struct panthor_device *ptdev = container_of(ddev, struct panthor_device, base);
 
-	cancel_work_sync(&ptdev->reset.work);
+	disable_work_sync(&ptdev->reset.work);
 	destroy_workqueue(ptdev->reset.wq);
 }
 
diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
index 9bf06e55eaeea..ceb249da8b336 100644
--- a/drivers/gpu/drm/panthor/panthor_fw.c
+++ b/drivers/gpu/drm/panthor/panthor_fw.c
@@ -1162,7 +1162,7 @@ void panthor_fw_unplug(struct panthor_device *ptdev)
 {
 	struct panthor_fw_section *section;
 
-	cancel_delayed_work_sync(&ptdev->fw->watchdog.ping_work);
+	disable_delayed_work_sync(&ptdev->fw->watchdog.ping_work);
 
 	if (!IS_ENABLED(CONFIG_PM) || pm_runtime_active(ptdev->base.dev)) {
 		/* Make sure the IRQ handler cannot be called after that point. */
diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
index b7595beaa0205..278434da8926d 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.c
+++ b/drivers/gpu/drm/panthor/panthor_sched.c
@@ -3879,8 +3879,9 @@ void panthor_sched_unplug(struct panthor_device *ptdev)
 {
 	struct panthor_scheduler *sched = ptdev->scheduler;
 
-	cancel_delayed_work_sync(&sched->tick_work);
+	disable_delayed_work_sync(&sched->tick_work);
 	disable_work_sync(&sched->fw_events_work);
+	disable_work_sync(&sched->sync_upd_work);
 
 	mutex_lock(&sched->lock);
 	if (sched->pm.has_ref) {
@@ -3898,8 +3899,6 @@ static void panthor_sched_fini(struct drm_device *ddev, void *res)
 	if (!sched || !sched->csg_slot_count)
 		return;
 
-	cancel_delayed_work_sync(&sched->tick_work);
-
 	if (sched->wq)
 		destroy_workqueue(sched->wq);
 
-- 
2.47.2