From: Viresh Kumar Date: Sat, 12 Jan 2013 05:14:40 +0000 (+0000) Subject: cpufreq: Don't use cpu removed during cpufreq_driver_unregister X-Git-Tag: v3.9-rc1~146^2~3^2~48 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6954ca9c8b5cbaf45c3e45a5a5a7450c6b55ab27;p=pandora-kernel.git cpufreq: Don't use cpu removed during cpufreq_driver_unregister This is how the core works: cpufreq_driver_unregister() - subsys_interface_unregister() - for_each_cpu() call cpufreq_remove_dev(), i.e. 0,1,2,3,4 when we unregister. cpufreq_remove_dev(): - Remove policy node - Call cpufreq_add_dev() for next cpu, sharing mask with removed cpu. i.e. When cpu 0 is removed, we call it for cpu 1. And when called for cpu 2, we call it for cpu 3. - cpufreq_add_dev() would call cpufreq_driver->init() - init would return mask as AND of 2, 3 and 4 for cluster A7. - cpufreq core would do online_cpu && policy->cpus Here is the BUG(). Because cpu hasn't died but we have just unregistered the cpufreq driver, online cpu would still have cpu 2 in it. And so thing go bad again. Solution: Keep cpumask of cpus that are registered with cpufreq core and clear cpus when we get a call from subsys_interface_unregister() via cpufreq_remove_dev(). Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- Reading git-diff-tree failed