[PATCH] x86: all cpu backtrace

[deliverable/linux.git] / arch / i386 / kernel / nmi.c

diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c
index eaafe233a5da83f4abbb2c17e670b8a46fa4edaa..171194ccb7bc480d0dc6cfbfbf06c07514d47d31 100644 (file)
--- a/arch/i386/kernel/nmi.c
+++ b/arch/i386/kernel/nmi.c
@@ -22,6 +22,7 @@
 #include <linux/percpu.h>
 #include <linux/dmi.h>
 #include <linux/kprobes.h>
+#include <linux/cpumask.h>
 
 #include <asm/smp.h>
 #include <asm/nmi.h>
@@ -42,6 +43,8 @@ int nmi_watchdog_enabled;
 static DEFINE_PER_CPU(unsigned long, perfctr_nmi_owner);
 static DEFINE_PER_CPU(unsigned long, evntsel_nmi_owner[3]);
 
+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)
  */
@@ -907,6 +910,16 @@ __kprobes int 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);
+       }
+
        sum = per_cpu(irq_stat, cpu).apic_timer_irqs;
 
        /* if the apic timer isn't firing, this cpu isn't doing much */
@@ -1033,6 +1046,19 @@ 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);