1 files changed, 15 insertions, 9 deletions

diff --git a/arch/i386/kernel/smp.c b/arch/i386/kernel/smp.c
index 68be7d0c7238..35f521612b20 100644
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -19,6 +19,7 @@
 #include <linux/mc146818rtc.h>
 #include <linux/cache.h>
 #include <linux/interrupt.h>
+#include <linux/cpu.h>
 #include <linux/module.h>
 
 #include <asm/mtrr.h>
@@ -164,7 +165,7 @@ void send_IPI_mask_bitmask(cpumask_t cpumask, int vector)
         unsigned long flags;
 
         local_irq_save(flags);
-                
+        WARN_ON(mask & ~cpus_addr(cpu_online_map)[0]);
         /*
          * Wait for idle.
          */
@@ -346,21 +347,21 @@ out:
 static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
                                                 unsigned long va)
 {
-        cpumask_t tmp;
         /*
          * A couple of (to be removed) sanity checks:
          *
-         * - we do not send IPIs to not-yet booted CPUs.
          * - current CPU must not be in mask
          * - mask must exist :)
          */
         BUG_ON(cpus_empty(cpumask));
-
-        cpus_and(tmp, cpumask, cpu_online_map);
-        BUG_ON(!cpus_equal(cpumask, tmp));
         BUG_ON(cpu_isset(smp_processor_id(), cpumask));
         BUG_ON(!mm);
 
+        /* If a CPU which we ran on has gone down, OK. */
+        cpus_and(cpumask, cpumask, cpu_online_map);
+        if (cpus_empty(cpumask))
+                return;
+
         /*
          * i'm not happy about this global shared spinlock in the
          * MM hot path, but we'll see how contended it is.
@@ -476,6 +477,7 @@ void flush_tlb_all(void)
  */
 void smp_send_reschedule(int cpu)
 {
+        WARN_ON(cpu_is_offline(cpu));
         send_IPI_mask(cpumask_of_cpu(cpu), RESCHEDULE_VECTOR);
 }
 
@@ -516,10 +518,15 @@ int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
  */
 {
         struct call_data_struct data;
-        int cpus = num_online_cpus()-1;
+        int cpus;
 
-        if (!cpus)
+        /* Holding any lock stops cpus from going down. */
+        spin_lock(&call_lock);
+        cpus = num_online_cpus() - 1;
+        if (!cpus) {
+                spin_unlock(&call_lock);
                 return 0;
+        }
 
         /* Can deadlock when called with interrupts disabled */
         WARN_ON(irqs_disabled());
@@ -531,7 +538,6 @@ int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
         if (wait)
                 atomic_set(&data.finished, 0);
 
-        spin_lock(&call_lock);
         call_data = &data;
         mb();