diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c index 1757074be994a75592f46e051f0beca24d4e0fa5..4978b8fe59e575a44ae76c5641a76930785e040b 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -34,6 +34,8 @@ | MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED \ | MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK) +static DEFINE_MUTEX(membarrier_ipi_mutex); + static void ipi_mb(void *info) { smp_mb(); /* IPIs should be serializing but paranoid. */ @@ -89,6 +91,7 @@ static int membarrier_global_expedited(void) if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL)) return -ENOMEM; + mutex_lock(&membarrier_ipi_mutex); cpus_read_lock(); rcu_read_lock(); for_each_online_cpu(cpu) { @@ -135,6 +138,7 @@ static int membarrier_global_expedited(void) * rq->curr modification in scheduler. */ smp_mb(); /* exit from system call is not a mb */ + mutex_unlock(&membarrier_ipi_mutex); return 0; } @@ -168,6 +172,7 @@ static int membarrier_private_expedited(int flags) if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL)) return -ENOMEM; + mutex_lock(&membarrier_ipi_mutex); cpus_read_lock(); rcu_read_lock(); for_each_online_cpu(cpu) { @@ -202,6 +207,7 @@ static int membarrier_private_expedited(int flags) * rq->curr modification in scheduler. */ smp_mb(); /* exit from system call is not a mb */ + mutex_unlock(&membarrier_ipi_mutex); return 0; }