1 files changed, 13 insertions, 8 deletions

diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index cfec478a4e42..8e740934bd1f 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -206,19 +206,22 @@ void
 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
                    unsigned long *sp, unsigned long bp, char *log_lvl)
 {
+        unsigned long *irq_stack_end;
+        unsigned long *irq_stack;
         unsigned long *stack;
+        int cpu;
         int i;
-        const int cpu = smp_processor_id();
-        unsigned long *irq_stack_end =
-                (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
-        unsigned long *irq_stack =
-                (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
+
+        preempt_disable();
+        cpu = smp_processor_id();
+
+        irq_stack_end   = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
+        irq_stack       = (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
 
         /*
-         * debugging aid: "show_stack(NULL, NULL);" prints the
-         * back trace for this cpu.
+         * Debugging aid: "show_stack(NULL, NULL);" prints the
+         * back trace for this cpu:
          */
-
         if (sp == NULL) {
                 if (task)
                         sp = (unsigned long *)task->thread.sp;
@@ -242,6 +245,8 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
                 printk(" %016lx", *stack++);
                 touch_nmi_watchdog();
         }
+        preempt_enable();
+
         printk("\n");
         show_trace_log_lvl(task, regs, sp, bp, log_lvl);
 }