[PATCH 6.19 225/781] drm/panthor: Fix NULL pointer dereference on panthor_fw_unplug

Greg Kroah-Hartman
2026-02-25T01:31:01Z

From: Karunika Choo <karunika.choo@arm.com>

[ Upstream commit 920c6af98e98e6afedf6318a75bac95af8415c6c ]

This patch removes the MCU halt and wait for halt procedures during
panthor_fw_unplug() as the MCU can be in a variety of states or the FW
may not even be loaded/initialized at all, the latter of which can lead
to a NULL pointer dereference.

It should be safe on unplug to just disable the MCU without waiting for
it to halt as it may not be able to.

Fixes: 514072549865 ("drm/panthor: Support GLB_REQ.STATE field for Mali-G1 GPUs")
Suggested-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Karunika Choo <karunika.choo@arm.com>
Reviewed-by: Liviu Dudau <liviu@dudau.co.uk>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patch.msgid.link/20251215203312.1084182-1-karunika.choo@arm.com
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/panthor/panthor_fw.c | 4 ----
1 file changed, 4 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
index 94a3cd6dfa6de..9533b1a31820e 100644
--- a/drivers/gpu/drm/panthor/panthor_fw.c
+++ b/drivers/gpu/drm/panthor/panthor_fw.c
@@ -1260,10 +1260,6 @@ void panthor_fw_unplug(struct panthor_device *ptdev)
if (ptdev->fw->irq.irq)
panthor_job_irq_suspend(&ptdev->fw->irq);

- panthor_fw_halt_mcu(ptdev);
- if (!panthor_fw_wait_mcu_halted(ptdev))
- drm_warn(&ptdev->base, "Failed to halt MCU on unplug");
-
panthor_fw_stop(ptdev);
}

--
2.51.0