[PATCH 4.20 066/171] lib/test_kmod.c: potential double free in error handling

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit db7ddeab3ce5d64c9696e70d61f45ea9909cd196 ]

There is a copy and paste bug so we set "config->test_driver" to NULL
twice instead of setting "config->test_fs".  Smatch complains that it
leads to a double free:

  lib/test_kmod.c:840 __kmod_config_init() warn: 'config->test_fs' double freed

Link: http://lkml.kernel.org/r/20190121140011.GA14283@kadam
Fixes: d9c6a72d6fa2 ("kmod: add test driver to stress test the module loader")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Acked-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 lib/test_kmod.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/test_kmod.c b/lib/test_kmod.c
index d82d022111e0..9cf77628fc91 100644
--- a/lib/test_kmod.c
+++ b/lib/test_kmod.c
@@ -632,7 +632,7 @@ static void __kmod_config_free(struct test_config *config)
 	config->test_driver = NULL;
 
 	kfree_const(config->test_fs);
-	config->test_driver = NULL;
+	config->test_fs = NULL;
 }
 
 static void kmod_config_free(struct kmod_test_device *test_dev)
-- 
2.19.1