diff --git a/xen/common/softirq.c b/xen/common/softirq.c index b83ad96d6c..00d676b62c 100644 --- a/xen/common/softirq.c +++ b/xen/common/softirq.c @@ -29,6 +29,7 @@ static void __do_softirq(unsigned long ignore_mask) { unsigned int i, cpu; unsigned long pending; + bool rcu_allowed = !(ignore_mask & (1ul << RCU_SOFTIRQ)); for ( ; ; ) { @@ -38,7 +39,7 @@ static void __do_softirq(unsigned long ignore_mask) */ cpu = smp_processor_id(); - if ( rcu_pending(cpu) ) + if ( rcu_allowed && rcu_pending(cpu) ) rcu_check_callbacks(cpu); if ( ((pending = (softirq_pending(cpu) & ~ignore_mask)) == 0) @@ -53,9 +54,16 @@ static void __do_softirq(unsigned long ignore_mask) void process_pending_softirqs(void) { + unsigned long ignore_mask = (1ul << SCHEDULE_SOFTIRQ) | + (1ul << SCHED_SLAVE_SOFTIRQ); + + /* Block RCU processing in case of rcu_read_lock() held. */ + if ( preempt_count() ) + ignore_mask |= 1ul << RCU_SOFTIRQ; + ASSERT(!in_irq() && local_irq_is_enabled()); /* Do not enter scheduler as it can preempt the calling context. */ - __do_softirq((1ul << SCHEDULE_SOFTIRQ) | (1ul << SCHED_SLAVE_SOFTIRQ)); + __do_softirq(ignore_mask); } void do_softirq(void)