1 files changed, 10 insertions, 10 deletions

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index d1590486204a..00f03d82e69a 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -96,6 +96,12 @@ static inline void cond_local_irq_disable(struct pt_regs *regs)
                 local_irq_disable();
 }
 
+/*
+ * In IST context, we explicitly disable preemption.  This serves two
+ * purposes: it makes it much less likely that we would accidentally
+ * schedule in IST context and it will force a warning if we somehow
+ * manage to schedule by accident.
+ */
 void ist_enter(struct pt_regs *regs)
 {
         if (user_mode(regs)) {
@@ -110,13 +116,7 @@ void ist_enter(struct pt_regs *regs)
                 rcu_nmi_enter();
         }
 
-        /*
-         * We are atomic because we're on the IST stack; or we're on
-         * x86_32, in which case we still shouldn't schedule; or we're
-         * on x86_64 and entered from user mode, in which case we're
-         * still atomic unless ist_begin_non_atomic is called.
-         */
-        preempt_count_add(HARDIRQ_OFFSET);
+        preempt_disable();
 
         /* This code is a bit fragile.  Test it. */
         RCU_LOCKDEP_WARN(!rcu_is_watching(), "ist_enter didn't work");
@@ -124,7 +124,7 @@ void ist_enter(struct pt_regs *regs)
 
 void ist_exit(struct pt_regs *regs)
 {
-        preempt_count_sub(HARDIRQ_OFFSET);
+        preempt_enable_no_resched();
 
         if (!user_mode(regs))
                 rcu_nmi_exit();
@@ -155,7 +155,7 @@ void ist_begin_non_atomic(struct pt_regs *regs)
         BUG_ON((unsigned long)(current_top_of_stack() -
                                current_stack_pointer()) >= THREAD_SIZE);
 
-        preempt_count_sub(HARDIRQ_OFFSET);
+        preempt_enable_no_resched();
 }
 
 /**
@@ -165,7 +165,7 @@ void ist_begin_non_atomic(struct pt_regs *regs)
  */
 void ist_end_non_atomic(void)
 {
-        preempt_count_add(HARDIRQ_OFFSET);
+        preempt_disable();
 }
 
 static nokprobe_inline int