linux-kernel - [PATCH 3/3] parport: fix freeing freed memory

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Date:	Mon, 15 Jun 2015 20:05:51 +0530
From:	Sudip Mukherjee <sudipm.mukherjee@...il.com>
To:	gregkh@...uxfoundation.org
Cc:	linux-kernel@...r.kernel.org,
	Sudip Mukherjee <sudipm.mukherjee@...il.com>
Subject: [PATCH 3/3] parport: fix freeing freed memory

After the reference count becomes 0 when put_device() is called, it will
execute the release callback where we are freeing all the allocated
memory associated with the device. So if we just continue on the error
path then we are again freeing devname and trying to dereference par_dev
which has already been free-ed in the release callback.

Signed-off-by: Sudip Mukherjee <sudip@...torindia.org>
---
 drivers/parport/share.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/parport/share.c b/drivers/parport/share.c
index 1efec44..c02b5f2 100644
--- a/drivers/parport/share.c
+++ b/drivers/parport/share.c
@@ -892,8 +892,10 @@ parport_register_dev_model(struct parport *port, const char *name,
 	par_dev->dev.release = free_pardevice;
 	par_dev->devmodel = true;
 	ret = device_register(&par_dev->dev);
-	if (ret)
-		goto err_put_dev;
+	if (ret) {
+		put_device(&par_dev->dev);
+		goto err_put_port;
+	}
 
 	/* Chain this onto the list */
 	par_dev->prev = NULL;
@@ -940,8 +942,6 @@ parport_register_dev_model(struct parport *port, const char *name,
 
 	return par_dev;
 
-err_put_dev:
-	put_device(&par_dev->dev);
 err_free_devname:
 	kfree(devname);
 err_free_par_dev:
-- 
1.8.1.2

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