4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: "Gustavo A. R. Silva" <garsilva@xxxxxxxxxxxxxx>
[ Upstream commit 63f1e05f7fe9ca509c60154d6a833abf96eecdc9 ]
df->governor is being dereferenced before it is null checked,
hence there is a potential null pointer dereference.
Notice that df->governor is being null checked at line 1004:
if (df->governor) {, which implies it might be null.
Fix this by null checking df->governor before dereferencing it.
Addresses-Coverity-ID: 1401988 ("Dereference before null check")
Fixes: bcf23c79c4e4 ("PM / devfreq: Fix available_governor sysfs")
Signed-off-by: Gustavo A. R. Silva <garsilva@xxxxxxxxxxxxxx>
Reviewed-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
Signed-off-by: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/devfreq/devfreq.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -943,7 +943,8 @@ static ssize_t governor_store(struct dev
if (df->governor == governor) {
ret = 0;
goto out;
- } else if (df->governor->immutable || governor->immutable) {
+ } else if ((df->governor && df->governor->immutable) ||
+ governor->immutable) {
ret = -EINVAL;
goto out;
}