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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Evgeniy Polyakov <zbr@ioremap.net>,
	Akira Shimahara <akira215corp@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Richard Fontana <rfontana@redhat.com>,
	Allison Randal <allison@lohutok.net>,
	linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] w1_therm: Free the correct variable
Date: Wed, 20 May 2020 15:00:19 +0300	[thread overview]
Message-ID: <20200520120019.GA172354@mwanda> (raw)

The problem is that we change "p_args" to point to the middle of the
string so when we free it at the end of the function it's not freeing
the same pointer that we originally allocated.

Fixes: e2c94d6f5720 ("w1_therm: adding alarm sysfs entry")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
From static analysis.  I guess it must not cause too much of a problem
at run time?

 drivers/w1/slaves/w1_therm.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c
index cc4b88056b33..a6c85e486671 100644
--- a/drivers/w1/slaves/w1_therm.c
+++ b/drivers/w1/slaves/w1_therm.c
@@ -1526,8 +1526,9 @@ static ssize_t alarms_store(struct device *device,
 	int temp, ret = -EINVAL;
 	char *token = NULL;
 	s8 tl, th, tt;	/* 1 byte per value + temp ring order */
-	char *p_args = kmalloc(size, GFP_KERNEL);
+	char *p_args, *orig;
 
+	p_args = orig = kmalloc(size, GFP_KERNEL);
 	/* Safe string copys as buf is const */
 	if (!p_args) {
 		dev_warn(device,
@@ -1611,7 +1612,7 @@ static ssize_t alarms_store(struct device *device,
 
 free_m:
 	/* free allocated memory */
-	kfree(p_args);
+	kfree(orig);
 
 	return size;
 }
-- 
2.26.2


             reply	other threads:[~2020-05-20 12:00 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-20 12:00 Dan Carpenter [this message]
2020-05-20 16:44 ` [PATCH] w1_therm: Free the correct variable Akira shimahara

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