This broke after a recent change "cedb70a cpufreq: Split __cpufreq_remove_dev() into two parts" from Srivatsa..
Consider a scenario where we have two CPUs in a policy (0 & 1) and we are removing cpu 1. On the call to __cpufreq_remove_dev_prepare() we have cleared 1 from policy->cpus and now on a call to __cpufreq_remove_dev_finish() we read cpumask_weight of policy->cpus, which will come as 1 and this code will behave as if we are removing the last cpu from policy :)
Fix it by clearing cpu mask in __cpufreq_remove_dev_finish() instead of __cpufreq_remove_dev_prepare().
Reviewed-by: Srivatsa S. Bhat srivatsa.bhat@linux.vnet.ibm.com Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- V1->V2: - sent separately without cleanup patches - use cpumask_any_but() instead of cpumask_first()
drivers/cpufreq/cpufreq.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 43c24aa..dbfe219 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1125,7 +1125,7 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy, int ret;
/* first sibling now owns the new sysfs dir */ - cpu_dev = get_cpu_device(cpumask_first(policy->cpus)); + cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu));
/* Don't touch sysfs files during light-weight tear-down */ if (frozen) @@ -1189,12 +1189,9 @@ static int __cpufreq_remove_dev_prepare(struct device *dev, policy->governor->name, CPUFREQ_NAME_LEN); #endif
- WARN_ON(lock_policy_rwsem_write(cpu)); + lock_policy_rwsem_read(cpu); cpus = cpumask_weight(policy->cpus); - - if (cpus > 1) - cpumask_clear_cpu(cpu, policy->cpus); - unlock_policy_rwsem_write(cpu); + unlock_policy_rwsem_read(cpu);
if (cpu != policy->cpu) { if (!frozen) @@ -1237,9 +1234,12 @@ static int __cpufreq_remove_dev_finish(struct device *dev, return -EINVAL; }
- lock_policy_rwsem_read(cpu); + WARN_ON(lock_policy_rwsem_write(cpu)); cpus = cpumask_weight(policy->cpus); - unlock_policy_rwsem_read(cpu); + + if (cpus > 1) + cpumask_clear_cpu(cpu, policy->cpus); + unlock_policy_rwsem_write(cpu);
/* If cpu is last user of policy, free policy */ if (cpus == 1) {