From: Rafael J. Wysocki Date: Wed, 9 May 2018 09:44:56 +0000 (+0200) Subject: cpufreq: schedutil: Avoid using invalid next_freq X-Git-Tag: Ubuntu-5.10.0-12.13~7890^2~1 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=97739501f207efe33145b918817f305b822987f8;p=mirror_ubuntu-hirsute-kernel.git cpufreq: schedutil: Avoid using invalid next_freq 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(). 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 --- diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 23ef19070137..e13df951aca7 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -305,7 +305,8 @@ 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 */