[PATCH v2 1/1] PM: QoS: Add check to make sure CPU freq is non-negative

From: Shivnandan Kumar
Date: Thu Jul 14 2022 - 09:44:19 EST

CPU frequency should never be negative.
If some client driver calls freq_qos_update_request with some
value greater than INT_MAX, then it will set max CPU freq at
fmax but it will add plist node with some negative priority.
plist node has priority from INT_MIN (highest) to INT_MAX
(lowest). Once priority is set as negative, another client
will not be able to reduce CPU frequency. Adding check to
make sure CPU freq is non-negative will fix this problem.

Signed-off-by: Shivnandan Kumar <quic_kshivnan@xxxxxxxxxxx>

-addressed comments from Rafael
-changed commit text accordingly

kernel/power/qos.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index ec7e1e85923e..27e6596f287a 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -531,7 +531,7 @@ int freq_qos_add_request(struct freq_constraints *qos,
int ret;

- if (IS_ERR_OR_NULL(qos) || !req)
+ if (IS_ERR_OR_NULL(qos) || !req || value < FREQ_QOS_MIN_DEFAULT_VALUE)
return -EINVAL;

if (WARN(freq_qos_request_active(req),
@@ -563,7 +563,7 @@ EXPORT_SYMBOL_GPL(freq_qos_add_request);
int freq_qos_update_request(struct freq_qos_request *req, s32 new_value)
- if (!req)
+ if (!req || new_value < FREQ_QOS_MIN_DEFAULT_VALUE)
return -EINVAL;

if (WARN(!freq_qos_request_active(req),