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From: Dinghao Liu <dinghao.liu@zju.edu.cn>
To: dinghao.liu@zju.edu.cn, kjlu@umn.edu
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>,
	Guenter Roeck <linux@roeck-us.net>,
	Alexander Sverdlin <alexander.sverdlin@nokia.com>,
	Krzysztof Sobota <krzysztof.sobota@nokia.com>,
	linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] watchdog: Fix double-free in watchdog_cdev_register
Date: Sun, 23 Aug 2020 15:13:38 +0800	[thread overview]
Message-ID: <20200823071338.15209-1-dinghao.liu@zju.edu.cn> (raw)

When misc_register() fails, wd_data will be released by the
release callback function watchdog_core_data_release(), so
we don't need to free it again. But when watchdog_kworker is
NULL, we should free wd_data to prevent memleak.

Fixes: cb36e29bb0e4b ("watchdog: initialize device before misc_register")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
---
 drivers/watchdog/watchdog_dev.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 6798addabd5a..8ee78e26feb1 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -994,8 +994,10 @@ static int watchdog_cdev_register(struct watchdog_device *wdd)
 	wd_data->wdd = wdd;
 	wdd->wd_data = wd_data;
 
-	if (IS_ERR_OR_NULL(watchdog_kworker))
+	if (IS_ERR_OR_NULL(watchdog_kworker)) {
+		kfree(wd_data);
 		return -ENODEV;
+	}
 
 	device_initialize(&wd_data->dev);
 	wd_data->dev.devt = MKDEV(MAJOR(watchdog_devt), wdd->id);
@@ -1021,7 +1023,6 @@ static int watchdog_cdev_register(struct watchdog_device *wdd)
 				pr_err("%s: a legacy watchdog module is probably present.\n",
 					wdd->info->identity);
 			old_wd_data = NULL;
-			kfree(wd_data);
 			return err;
 		}
 	}
-- 
2.17.1


             reply	other threads:[~2020-08-23  7:14 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-23  7:13 Dinghao Liu [this message]
2020-08-23 19:06 ` [PATCH] watchdog: Fix double-free in watchdog_cdev_register Guenter Roeck
2020-08-24  2:13   ` dinghao.liu

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