From: Ezequiel Garcia <ezequiel@collabora.com>
Date: Fri, 21 Jun 2019 18:39:49 -0300
Subject: PM / devfreq: Fix kernel oops on governor module load
Git-commit: 7544fd7f384591038646d3cd9efb311ab4509e24
Patch-mainline: 5.4-rc1
References: bnc#1151927 5.3.4

A bit unexpectedly (but still documented), request_module may
return a positive value, in case of a modprobe error.
This is currently causing issues in the devfreq framework.

When a request_module exits with a positive value, we currently
return that via ERR_PTR. However, because the value is positive,
it's not a ERR_VALUE proper, and is therefore treated as a
valid struct devfreq_governor pointer, leading to a kernel oops.

Fix this by returning -EINVAL if request_module returns a positive
value.

Fixes: b53b0128052ff ("PM / devfreq: Fix static checker warning in try_then_request_governor")
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/devfreq/devfreq.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -254,7 +254,7 @@ static struct devfreq_governor *try_then
 		/* Restore previous state before return */
 		mutex_lock(&devfreq_list_lock);
 		if (err)
-			return ERR_PTR(err);
+			return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
 
 		governor = find_devfreq_governor(name);
 	}