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 <[email protected]> Signed-off-by: Viresh Kumar <[email protected]> --- 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) { -- 1.7.12.rc2.18.g61b472e -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
