From 9a50a29954cf1fc61ecf7cf497a5237565093c5e Mon Sep 17 00:00:00 2001
From: Samuel Holland <samuel@sholland.org>
Date: Wed, 15 Jun 2022 00:42:53 -0500
Subject: drm/sun4i: Fix crash during suspend after component bind failure
Git-commit: 1342b5b23da9559a1578978eaff7f797d8a87d91
Patch-mainline: v5.19-rc4
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
If the component driver fails to bind, or is unbound, the driver data
for the top-level platform device points to a freed drm_device. If the
system is then suspended, the driver passes this dangling pointer to
drm_mode_config_helper_suspend(), which crashes.
Fix this by only setting the driver data while the platform driver holds
a reference to the drm_device.
Fixes: 624b4b48d9d8 ("drm: sun4i: Add support for suspending the display driver")
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220615054254.16352-1-samuel@sholland.org
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/sun4i/sun4i_drv.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/sun4i/sun4i_drv.c b/drivers/gpu/drm/sun4i/sun4i_drv.c
index 275f7e4a03ae..8841dba989ee 100644
--- a/drivers/gpu/drm/sun4i/sun4i_drv.c
+++ b/drivers/gpu/drm/sun4i/sun4i_drv.c
@@ -73,7 +73,6 @@ static int sun4i_drv_bind(struct device *dev)
goto free_drm;
}
- dev_set_drvdata(dev, drm);
drm->dev_private = drv;
INIT_LIST_HEAD(&drv->frontend_list);
INIT_LIST_HEAD(&drv->engine_list);
@@ -114,6 +113,8 @@ static int sun4i_drv_bind(struct device *dev)
drm_fbdev_generic_setup(drm, 32);
+ dev_set_drvdata(dev, drm);
+
return 0;
finish_poll:
@@ -130,6 +131,7 @@ static void sun4i_drv_unbind(struct device *dev)
{
struct drm_device *drm = dev_get_drvdata(dev);
+ dev_set_drvdata(dev, NULL);
drm_dev_unregister(drm);
drm_kms_helper_poll_fini(drm);
drm_atomic_helper_shutdown(drm);
--
2.38.1