| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 46/62] cpufreq: schedutil: Avoid using invalid next_freq | Date | Mon, 14 May 2018 08:49:02 +0200 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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().
Fixes: b7eaf1aab9f8 (cpufreq: schedutil: Avoid reducing frequency of busy CPUs prematurely) Reported-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: 4.12+ <stable@vger.kernel.org> # 4.12+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- kernel/sched/cpufreq_schedutil.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -282,7 +282,8 @@ static void sugov_update_single(struct u * 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 */
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