Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fix from Ingo Molnar:
 "irq-tracing fixlet"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tracing: Add irq_enter/exit() in smp_trace_reschedule_interrupt()

1 files changed, 18 insertions, 11 deletions

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index f4fe0b88..cdaa347 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -265,23 +265,30 @@ void smp_reschedule_interrupt(struct pt_regs *regs)
 	 */
 }
 
-void smp_trace_reschedule_interrupt(struct pt_regs *regs)
+static inline void smp_entering_irq(void)
 {
 	ack_APIC_irq();
+	irq_enter();
+}
+
+void smp_trace_reschedule_interrupt(struct pt_regs *regs)
+{
+	/*
+	 * Need to call irq_enter() before calling the trace point.
+	 * __smp_reschedule_interrupt() calls irq_enter/exit() too (in
+	 * scheduler_ipi(). This is OK, since those functions are allowed
+	 * to nest.
+	 */
+	smp_entering_irq();
 	trace_reschedule_entry(RESCHEDULE_VECTOR);
 	__smp_reschedule_interrupt();
 	trace_reschedule_exit(RESCHEDULE_VECTOR);
+	exiting_irq();
 	/*
 	 * KVM uses this interrupt to force a cpu out of guest mode
 	 */
 }
 
-static inline void call_function_entering_irq(void)
-{
-	ack_APIC_irq();
-	irq_enter();
-}
-
 static inline void __smp_call_function_interrupt(void)
 {
 	generic_smp_call_function_interrupt();
@@ -290,14 +297,14 @@ static inline void __smp_call_function_interrupt(void)
 
 void smp_call_function_interrupt(struct pt_regs *regs)
 {
-	call_function_entering_irq();
+	smp_entering_irq();
 	__smp_call_function_interrupt();
 	exiting_irq();
 }
 
 void smp_trace_call_function_interrupt(struct pt_regs *regs)
 {
-	call_function_entering_irq();
+	smp_entering_irq();
 	trace_call_function_entry(CALL_FUNCTION_VECTOR);
 	__smp_call_function_interrupt();
 	trace_call_function_exit(CALL_FUNCTION_VECTOR);
@@ -312,14 +319,14 @@ static inline void __smp_call_function_single_interrupt(void)
 
 void smp_call_function_single_interrupt(struct pt_regs *regs)
 {
-	call_function_entering_irq();
+	smp_entering_irq();
 	__smp_call_function_single_interrupt();
 	exiting_irq();
 }
 
 void smp_trace_call_function_single_interrupt(struct pt_regs *regs)
 {
-	call_function_entering_irq();
+	smp_entering_irq();
 	trace_call_function_single_entry(CALL_FUNCTION_SINGLE_VECTOR);
 	__smp_call_function_single_interrupt();
 	trace_call_function_single_exit(CALL_FUNCTION_SINGLE_VECTOR);