linux-kernel - [PATCH v5] [ARM] fix reference leak in locomo_init_one

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Message-Id: <20250116070724.2171300-1-make24@iscas.ac.cn>
Date: Thu, 16 Jan 2025 15:07:24 +0800
From: Ma Ke <make24@...as.ac.cn>
To: linux@...linux.org.uk,
	make24@...as.ac.cn,
	sumit.garg@...aro.org,
	gregkh@...uxfoundation.org,
	elder@...nel.org
Cc: linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Subject: [PATCH v5] [ARM] fix reference leak in locomo_init_one_child()

Once device_register() failed, we should call put_device() to
decrement reference count for cleanup. Or it could cause memory leak.

As comment of device_register() says, 'NOTE: _Never_ directly free
@dev after calling this function, even if it returned an error! Always
use put_device() to give up the reference initialized in this function
instead.'

Found by code review.

Cc: stable@...r.kernel.org
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Ma Ke <make24@...as.ac.cn>
---
Changes in v5:
- modified the bug description as suggestions;
Changes in v4:
- deleted the redundant initialization;
Changes in v3:
- modified the patch as suggestions;
Changes in v2:
- modified the patch as suggestions.
---
 arch/arm/common/locomo.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/arch/arm/common/locomo.c b/arch/arm/common/locomo.c
index cb6ef449b987..45106066a17f 100644
--- a/arch/arm/common/locomo.c
+++ b/arch/arm/common/locomo.c
@@ -223,10 +223,8 @@ locomo_init_one_child(struct locomo *lchip, struct locomo_dev_info *info)
 	int ret;
 
 	dev = kzalloc(sizeof(struct locomo_dev), GFP_KERNEL);
-	if (!dev) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (!dev)
+		return -ENOMEM;
 
 	/*
 	 * If the parent device has a DMA mask associated with it,
@@ -254,10 +252,9 @@ locomo_init_one_child(struct locomo *lchip, struct locomo_dev_info *info)
 			NO_IRQ : lchip->irq_base + info->irq[0];
 
 	ret = device_register(&dev->dev);
-	if (ret) {
- out:
-		kfree(dev);
-	}
+	if (ret)
+		put_device(&dev->dev);
+
 	return ret;
 }
 
-- 
2.25.1