nmi_backtrace: generate one-line reports for idle cpus

[cascardo/linux.git] / lib / nmi_backtrace.c

diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c
index 393a3cc..7555475 100644 (file)
--- a/lib/nmi_backtrace.c
+++ b/lib/nmi_backtrace.c
@@ -16,6 +16,7 @@
 #include <linux/delay.h>
 #include <linux/kprobes.h>
 #include <linux/nmi.h>
+#include <linux/cpu.h>
 
 #ifdef arch_trigger_cpumask_backtrace
 /* For reliability, we're prepared to waste bits here. */
@@ -87,11 +88,16 @@ bool nmi_cpu_backtrace(struct pt_regs *regs)
        int cpu = smp_processor_id();
 
        if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
-               pr_warn("NMI backtrace for cpu %d\n", cpu);
-               if (regs)
-                       show_regs(regs);
-               else
-                       dump_stack();
+               if (regs && cpu_in_idle(instruction_pointer(regs))) {
+                       pr_warn("NMI backtrace for cpu %d skipped: idling at pc %#lx\n",
+                               cpu, instruction_pointer(regs));
+               } else {
+                       pr_warn("NMI backtrace for cpu %d\n", cpu);
+                       if (regs)
+                               show_regs(regs);
+                       else
+                               dump_stack();
+               }
                cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
                return true;
        }