From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Race in cpufreq_add_dev()?
Date: Thu, 06 Jul 2006 12:35:37 -0700
Message-ID: <44AD6609.1080604@goop.org>
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cpufreq_add_dev contains the test:

#ifdef CONFIG_SMP
	/* check whether a different CPU already registered this
	 * CPU because it is in the same boat. */
	policy = cpufreq_cpu_get(cpu);
	if (unlikely(policy)) {
		cpufreq_cpu_put(policy);
		cpufreq_debug_enable_ratelimit();
		return 0;
	}
#endif

I don't see what prevents two CPUs from racing through here.  Both could 
perform this test and find that there's no policy for the CPU, and then 
both will attempt to add it.  Or is there something else which 
serializes multiple CPUs through this code?

    J