test_kmod: fix the lock in register_test_dev_kmod()

We accidentally just drop the lock twice instead of taking it and then
releasing it.  This isn't a big issue unless you are adding more than
one device to test on, and the kmod.sh doesn't do that yet, however this
obviously is the correct thing to do.

[mcgrof@kernel.org: massaged subject, explain what happens]
Link: http://lkml.kernel.org/r/20170802211450.27928-5-mcgrof@kernel.org
Fixes: 39258f448d71 ("kmod: add test driver to stress test the module loader")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Michal Marek <mmarek@suse.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/test_kmod.c b/lib/test_kmod.c
index 8fc0a7a19c8399c6f3f8f4ff7dbf795064239ee8..1bc06bbfc97a4818574de4fa27200b4ab519b679 100644 (file)
--- a/lib/test_kmod.c
+++ b/lib/test_kmod.c
@@ -1146,7 +1146,7 @@ static struct kmod_test_device *register_test_dev_kmod(void)
        struct kmod_test_device *test_dev = NULL;
        int ret;
 
-       mutex_unlock(&reg_dev_mutex);
+       mutex_lock(&reg_dev_mutex);
 
        /* int should suffice for number of devices, test for wrap */
        if (unlikely(num_test_devs + 1) < 0) {