[PATCH 5.15 042/135] drm/sun4i: Fix crash during suspend after component bind failure

Greg Kroah-Hartman
2022-06-27T11:41:51Z

From: Samuel Holland <samuel@sholland.org>

[ Upstream commit 1342b5b23da9559a1578978eaff7f797d8a87d91 ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 54dd562e294c..5b7061e2bca4 100644
--- a/drivers/gpu/drm/sun4i/sun4i_drv.c
+++ b/drivers/gpu/drm/sun4i/sun4i_drv.c
@@ -72,7 +72,6 @@ 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);
@@ -113,6 +112,8 @@ static int sun4i_drv_bind(struct device *dev)

drm_fbdev_generic_setup(drm, 32);

+ dev_set_drvdata(dev, drm);
+
return 0;

finish_poll:
@@ -129,6 +130,7 @@ 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);
--
2.35.1