From 2526d1a2945583ba8f67eac5d6c38023f57edaca Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Wed, 7 Jul 2021 11:51:12 +0200
Subject: drm/vc4: hdmi: Only call into DRM framework if registered
Git-commit: 44fe9f90eb9d2533d049b4ba09540eed6cad9f49
Patch-mainline: v5.15-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
Our hotplug handler will currently call the drm_kms_helper_hotplug_event
every time a hotplug interrupt is called.
However, since the device is registered after all the drivers have
finished their bind callback, we have a window between when we install
our interrupt handler and when drm_dev_register() is eventually called
where our handler can run and call drm_kms_helper_hotplug_event but the
device hasn't been registered yet, causing a null pointer dereference.
Fix this by making sure we only call drm_kms_helper_hotplug_event if our
device has been properly registered.
Fixes: f4790083c7c2 ("drm/vc4: hdmi: Rely on interrupts to handle hotplug")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210707095112.1469670-4-maxime@cerno.tech
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/vc4/vc4_hdmi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index a5280c97f3c1..5dbb533b969e 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -1574,7 +1574,7 @@ static irqreturn_t vc4_hdmi_hpd_irq_thread(int irq, void *priv)
struct vc4_hdmi *vc4_hdmi = priv;
struct drm_device *dev = vc4_hdmi->connector.dev;
- if (dev)
+ if (dev && dev->registered)
drm_kms_helper_hotplug_event(dev);
return IRQ_HANDLED;
--
2.38.1