From 25da1fb9b2e49ea4474735a109d8e5608e9d980e Mon Sep 17 00:00:00 2001 From: Sultan Alsawaf Date: Sat, 14 Jan 2023 18:37:30 +0530 Subject: [PATCH] qos: Don't allow userspace to impose restrictions on CPU idle levels Giving userspace intimate control over CPU latency requirements is nonsense. Userspace can't even stop itself from being preempted, so there's no reason for it to have access to a mechanism primarily used to eliminate CPU delays on the order of microseconds. Remove userspace's ability to send pm_qos requests so that it can't hurt power consumption. Signed-off-by: Sultan Alsawaf Signed-off-by: Panchajanya1999 --- kernel/power/qos.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/power/qos.c b/kernel/power/qos.c index f2ceada58..2027e7e6b 100755 --- a/kernel/power/qos.c +++ b/kernel/power/qos.c @@ -380,6 +380,9 @@ static ssize_t cpu_latency_qos_write(struct file *filp, const char __user *buf, { s32 value; + /* Don't let userspace impose restrictions on CPU idle levels */ + return count; + if (count == sizeof(s32)) { if (copy_from_user(&value, buf, sizeof(s32))) return -EFAULT;