Commit 7544fd7f authored Jun 21, 2019 by Ezequiel Garcia Committed by MyungJoo Ham Aug 24, 2019

PM / devfreq: Fix kernel oops on governor module load



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: b53b0128 ("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>

parent 0a453aca

drivers/devfreq/devfreq.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -254,7 +254,7 @@ static struct devfreq_governor try_then_request_governor(const char name)
		/* 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);
		}

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