From 28b44d1dd92c5863f0fac41f143decfaa100757f Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 9 May 2018 11:44:56 +0200 Subject: [PATCH] cpufreq: schedutil: Avoid using invalid next_freq. commit 97739501f207efe33145b918817f305b822987f8 upstream. If the next_freq field of struct sugov_policy is set to UINT_MAX, it shouldn't be used for updating the CPU frequency (this is a special "invalid" value), but after commit b7eaf1aab9f8 (cpufreq: schedutil: Avoid reducing frequency of busy CPUs prematurely) it may be passed as the new frequency to sugov_update_commit() in sugov_update_single(). Fix that by adding an extra check for the special UINT_MAX value of next_freq to sugov_update_single(). Change-Id: I516963d8b0fda677e9d82290c0f3d4dc3cb6e477 Fixes: b7eaf1aab9f8 (cpufreq: schedutil: Avoid reducing frequency of busy CPUs prematurely) Reported-by: Viresh Kumar Cc: 4.12+ # 4.12+ Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- kernel/sched/cpufreq_schedutil.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index dee7a12c6d1b..af0d2ef5b2ae 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -368,7 +368,8 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, * Do not reduce the frequency if the CPU has not been idle * recently, as the reduction is likely to be premature then. */ - if (busy && next_f < sg_policy->next_freq) { + if (busy && next_f < sg_policy->next_freq && + sg_policy->next_freq != UINT_MAX) { next_f = sg_policy->next_freq; /* Reset cached freq as next_freq has changed */ -- 2.20.1