1 files changed, 6 insertions, 2 deletions

diff --git a/arch/x86_64/kernel/smp.c b/arch/x86_64/kernel/smp.c
index 4f67697f5036..af1ec4d23cf8 100644
--- a/arch/x86_64/kernel/smp.c
+++ b/arch/x86_64/kernel/smp.c
@@ -376,16 +376,20 @@ int smp_call_function_single (int cpu, void (*func) (void *info), void *info,
         /* prevent preemption and reschedule on another processor */
         int me = get_cpu();
         if (cpu == me) {
-                WARN_ON(1);
                 put_cpu();
-                return -EBUSY;
+                return 0;
         }
+
+        /* Can deadlock when called with interrupts disabled */
+        WARN_ON(irqs_disabled());
+
         spin_lock_bh(&call_lock);
         __smp_call_function_single(cpu, func, info, nonatomic, wait);
         spin_unlock_bh(&call_lock);
         put_cpu();
         return 0;
 }
+EXPORT_SYMBOL(smp_call_function_single);
 
 /*
  * this function sends a 'generic call function' IPI to all other CPUs