[PATCH] drm: sti: fix device leaks at component probe

Johan Hovold posted 1 patch 1 week, 2 days ago
drivers/gpu/drm/sti/sti_vtg.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
[PATCH] drm: sti: fix device leaks at component probe
Posted by Johan Hovold 1 week, 2 days ago
Make sure to drop the references taken to the vtg devices by
of_find_device_by_node() when looking up their driver data during
component probe.

Note that holding a reference to a platform device does not prevent its
driver data from going away so there is no point in keeping the
reference after the lookup helper returns.

Fixes: cc6b741c6f63 ("drm: sti: remove useless fields from vtg structure")
Cc: stable@vger.kernel.org	# 4.16
Cc: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/gpu/drm/sti/sti_vtg.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/sti/sti_vtg.c b/drivers/gpu/drm/sti/sti_vtg.c
index ee81691b3203..ce6bc7e7b135 100644
--- a/drivers/gpu/drm/sti/sti_vtg.c
+++ b/drivers/gpu/drm/sti/sti_vtg.c
@@ -143,12 +143,17 @@ struct sti_vtg {
 struct sti_vtg *of_vtg_find(struct device_node *np)
 {
 	struct platform_device *pdev;
+	struct sti_vtg *vtg;
 
 	pdev = of_find_device_by_node(np);
 	if (!pdev)
 		return NULL;
 
-	return (struct sti_vtg *)platform_get_drvdata(pdev);
+	vtg = platform_get_drvdata(pdev);
+
+	put_device(&pdev->dev);
+
+	return vtg;
 }
 
 static void vtg_reset(struct sti_vtg *vtg)
-- 
2.49.1
Re: [PATCH] drm: sti: fix device leaks at component probe
Posted by Markus Elfring 1 week, 2 days ago
> Make sure to drop the references taken to the vtg devices by

                                                VTG device?


> of_find_device_by_node() when looking up their driver data during
> component probe.
…

How do you think about to increase the application of scope-based resource management?
https://elixir.bootlin.com/linux/v6.17-rc7/source/include/linux/device.h#L1180

Can a summary phrase like “Prevent device leak in of_vtg_find()” be nicer?

Regards,
Markus