4.15-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 @@ -996,7 +996,8 @@ 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; }