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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-07-30 00:32:00 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-08-11 18:35:24 -0700
commite9ef4410a75bea04e5f9e30c41fba0ebfa9b7559 (patch)
tree5112ac021251fea5587b8c09422d368534d6e147 /kernel/time
parent657e142082bec684725383eccd54e4ace5a2c293 (diff)
downloadlinaro-lsk-e9ef4410a75bea04e5f9e30c41fba0ebfa9b7559.tar.gz
cpufreq: Fix cpufreq driver module refcount balance after suspend/resume
commit 2a99859932281ed6c2ecdd988855f8f6838f6743 upstream. Since cpufreq_cpu_put() called by __cpufreq_remove_dev() drops the driver module refcount, __cpufreq_remove_dev() causes that refcount to become negative for the cpufreq driver after a suspend/resume cycle. This is not the only bad thing that happens there, however, because kobject_put() should only be called for the policy kobject at this point if the CPU is not the last one for that policy. Namely, if the given CPU is the last one for that policy, the policy kobject's refcount should be 1 at this point, as set by cpufreq_add_dev_interface(), and only needs to be dropped once for the kobject to go away. This actually happens under the cpu == 1 check, so it need not be done before by cpufreq_cpu_put(). On the other hand, if the given CPU is not the last one for that policy, this means that cpufreq_add_policy_cpu() has been called at least once for that policy and cpufreq_cpu_get() has been called for it too. To balance that cpufreq_cpu_get(), we need to call cpufreq_cpu_put() in that case. Thus, to fix the described problem and keep the reference counters balanced in both cases, move the cpufreq_cpu_get() call in __cpufreq_remove_dev() to the code path executed only for CPUs that share the policy with other CPUs. Reported-and-tested-by: Toralf Förster <toralf.foerster@gmx.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/time')
0 files changed, 0 insertions, 0 deletions