linux-kernel - [PATCH AUTOSEL 5.15 3/9] powercap: call put_device() on an error path in powercap_register_control

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Message-Id: <20250211013230.4098681-3-sashal@kernel.org>
Date: Mon, 10 Feb 2025 20:32:24 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Joe Hattori <joe@...is.s.u-tokyo.ac.jp>,
	"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
	Sasha Levin <sashal@...nel.org>,
	rafael@...nel.org,
	linux-pm@...r.kernel.org
Subject: [PATCH AUTOSEL 5.15 3/9] powercap: call put_device() on an error path in powercap_register_control_type()

From: Joe Hattori <joe@...is.s.u-tokyo.ac.jp>

[ Upstream commit 93c66fbc280747ea700bd6199633d661e3c819b3 ]

powercap_register_control_type() calls device_register(), but does not
release the refcount of the device when it fails.

Call put_device() before returning an error to balance the refcount.

Since the kfree(control_type) will be done by powercap_release(), remove
the lines in powercap_register_control_type() before returning the error.

This bug was found by an experimental verifier that I am developing.

Signed-off-by: Joe Hattori <joe@...is.s.u-tokyo.ac.jp>
Link: https://patch.msgid.link/20250110010554.1583411-1-joe@pf.is.s.u-tokyo.ac.jp
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/powercap/powercap_sys.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/powercap/powercap_sys.c b/drivers/powercap/powercap_sys.c
index ff736b006198f..fd475e463d1fa 100644
--- a/drivers/powercap/powercap_sys.c
+++ b/drivers/powercap/powercap_sys.c
@@ -626,8 +626,7 @@ struct powercap_control_type *powercap_register_control_type(
 	dev_set_name(&control_type->dev, "%s", name);
 	result = device_register(&control_type->dev);
 	if (result) {
-		if (control_type->allocated)
-			kfree(control_type);
+		put_device(&control_type->dev);
 		return ERR_PTR(result);
 	}
 	idr_init(&control_type->idr);
-- 
2.39.5