linux-kernel - [PATCH] firmware: meson_sm: fix device leak at probe

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Message-ID: <20250725074019.8765-1-johan@kernel.org>
Date: Fri, 25 Jul 2025 09:40:19 +0200
From: Johan Hovold <johan@...nel.org>
To: Neil Armstrong <neil.armstrong@...aro.org>
Cc: Kevin Hilman <khilman@...libre.com>,
	Jerome Brunet <jbrunet@...libre.com>,
	Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
	Carlo Caione <ccaione@...libre.com>,
	linux-amlogic@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Johan Hovold <johan@...nel.org>,
	stable@...r.kernel.org
Subject: [PATCH] firmware: meson_sm: fix device leak at probe

Make sure to drop the reference to the secure monitor device taken by
of_find_device_by_node() when looking up its driver data on behalf of
other drivers (e.g. during probe).

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

Fixes: 8cde3c2153e8 ("firmware: meson_sm: Rework driver as a proper platform driver")
Cc: stable@...r.kernel.org	# 5.5
Cc: Carlo Caione <ccaione@...libre.com>
Signed-off-by: Johan Hovold <johan@...nel.org>
---
 drivers/firmware/meson/meson_sm.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/meson/meson_sm.c b/drivers/firmware/meson/meson_sm.c
index f25a9746249b..3ab67aaa9e5d 100644
--- a/drivers/firmware/meson/meson_sm.c
+++ b/drivers/firmware/meson/meson_sm.c
@@ -232,11 +232,16 @@ EXPORT_SYMBOL(meson_sm_call_write);
 struct meson_sm_firmware *meson_sm_get(struct device_node *sm_node)
 {
 	struct platform_device *pdev = of_find_device_by_node(sm_node);
+	struct meson_sm_firmware *fw;
 
 	if (!pdev)
 		return NULL;
 
-	return platform_get_drvdata(pdev);
+	fw = platform_get_drvdata(pdev);
+
+	put_device(&pdev->dev);
+
+	return fw;
 }
 EXPORT_SYMBOL_GPL(meson_sm_get);
 
-- 
2.49.1