From e1fb7646f1092a0e9baa0007983563092f3ab93d Mon Sep 17 00:00:00 2001 From: Lianwei Wang Date: Thu, 16 May 2013 12:07:23 +0800 Subject: [PATCH] cpufreq: interactive: fix race on cpufreq TRANSITION notifier The cpufreq TRANSTION notifier callback does not check the governor_enabled state on affected CPUS, which will case kernel panic in update_load because the policy object maybe NULL or invalid when governor_enabled is false. Change-Id: Ie0f1718124f61e2f9b5da57abc6981ada5b83908 Signed-off-by: Lianwei Wang --- drivers/cpufreq/cpufreq_interactive.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c index 7303f50a1180..691923d6c868 100644 --- a/drivers/cpufreq/cpufreq_interactive.c +++ b/drivers/cpufreq/cpufreq_interactive.c @@ -634,9 +634,19 @@ static int cpufreq_interactive_notifier( for_each_cpu(cpu, pcpu->policy->cpus) { struct cpufreq_interactive_cpuinfo *pjcpu = &per_cpu(cpuinfo, cpu); + if (cpu != freq->cpu) { + if (!down_read_trylock(&pjcpu->enable_sem)) + continue; + if (!pjcpu->governor_enabled) { + up_read(&pjcpu->enable_sem); + continue; + } + } spin_lock_irqsave(&pjcpu->load_lock, flags); update_load(cpu); spin_unlock_irqrestore(&pjcpu->load_lock, flags); + if (cpu != freq->cpu) + up_read(&pjcpu->enable_sem); } up_read(&pcpu->enable_sem); -- 2.34.1