diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c index 3d2825408e3a..0836235bbd59 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -162,6 +162,8 @@ | MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK \ | MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK) +static DEFINE_MUTEX(membarrier_ipi_mutex); + static void ipi_mb(void *info) { smp_mb(); /* IPIs should be serializing but paranoid. */ @@ -259,6 +261,7 @@ 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) { @@ -304,6 +307,8 @@ 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; } @@ -347,6 +352,7 @@ static int membarrier_private_expedited(int flags, int cpu_id) if (cpu_id < 0 && !zalloc_cpumask_var(&tmpmask, GFP_KERNEL)) return -ENOMEM; + mutex_lock(&membarrier_ipi_mutex); cpus_read_lock(); if (cpu_id >= 0) { @@ -419,6 +425,7 @@ out: * rq->curr modification in scheduler. */ smp_mb(); /* exit from system call is not a mb */ + mutex_unlock(&membarrier_ipi_mutex); return 0; } @@ -460,6 +467,7 @@ static int sync_runqueues_membarrier_state(struct mm_struct *mm) * between threads which are users of @mm has its membarrier state * updated. */ + mutex_lock(&membarrier_ipi_mutex); cpus_read_lock(); rcu_read_lock(); for_each_online_cpu(cpu) { @@ -476,6 +484,7 @@ static int sync_runqueues_membarrier_state(struct mm_struct *mm) free_cpumask_var(tmpmask); cpus_read_unlock(); + mutex_unlock(&membarrier_ipi_mutex); return 0; }