[PATCH] x86: all cpu backtrace

[deliverable/linux.git] / arch / x86_64 / kernel / nmi.c

diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c
index 7af9cb3e2d99a8e71e54d89c170245580b2d470e..27e95e7922c16e6f2d637f9b677927cc049b989e 100644 (file)
--- a/arch/x86_64/kernel/nmi.c
+++ b/arch/x86_64/kernel/nmi.c
@@ -12,14 +12,15 @@
  *  Mikael Pettersson  : PM converted to driver model. Disable/enable API.
  */
 
+#include <linux/nmi.h>
 #include <linux/mm.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/sysdev.h>
-#include <linux/nmi.h>
 #include <linux/sysctl.h>
 #include <linux/kprobes.h>
+#include <linux/cpumask.h>
 
 #include <asm/smp.h>
 #include <asm/nmi.h>
@@ -41,6 +42,8 @@ int panic_on_unrecovered_nmi;
 static DEFINE_PER_CPU(unsigned, perfctr_nmi_owner);
 static DEFINE_PER_CPU(unsigned, evntsel_nmi_owner[2]);
 
+static cpumask_t backtrace_mask = CPU_MASK_NONE;
+
 /* this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's
  * offset from MSR_P4_BSU_ESCR0.  It will be the max for all platforms (for now)
  */
@@ -782,6 +785,7 @@ int __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
 {
        int sum;
        int touched = 0;
+       int cpu = smp_processor_id();
        struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk);
        u64 dummy;
        int rc=0;
@@ -799,6 +803,16 @@ int __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason)
                touched = 1;
        }
 
+       if (cpu_isset(cpu, backtrace_mask)) {
+               static DEFINE_SPINLOCK(lock);   /* Serialise the printks */
+
+               spin_lock(&lock);
+               printk("NMI backtrace for cpu %d\n", cpu);
+               dump_stack();
+               spin_unlock(&lock);
+               cpu_clear(cpu, backtrace_mask);
+       }
+
 #ifdef CONFIG_X86_MCE
        /* Could check oops_in_progress here too, but it's safer
           not too */
@@ -931,6 +945,19 @@ int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file,
 
 #endif
 
+void __trigger_all_cpu_backtrace(void)
+{
+       int i;
+
+       backtrace_mask = cpu_online_map;
+       /* Wait for up to 10 seconds for all CPUs to do the backtrace */
+       for (i = 0; i < 10 * 1000; i++) {
+               if (cpus_empty(backtrace_mask))
+                       break;
+               mdelay(1);
+       }
+}
+
 EXPORT_SYMBOL(nmi_active);
 EXPORT_SYMBOL(nmi_watchdog);
 EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi);