--- zzzz-none-000/linux-3.10.107/arch/x86/kernel/apic/hw_nmi.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/x86/kernel/apic/hw_nmi.c	2021-02-04 17:41:59.000000000 +0000
@@ -18,6 +18,7 @@
 #include <linux/nmi.h>
 #include <linux/module.h>
 #include <linux/delay.h>
+#include <linux/seq_buf.h>
 
 #ifdef CONFIG_HARDLOCKUP_DETECTOR
 u64 hw_nmi_get_sample_period(int watchdog_thresh)
@@ -27,59 +28,25 @@
 #endif
 
 #ifdef arch_trigger_all_cpu_backtrace
-/* For reliability, we're prepared to waste bits here. */
-static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
-
-/* "in progress" flag of arch_trigger_all_cpu_backtrace */
-static unsigned long backtrace_flag;
-
-void arch_trigger_all_cpu_backtrace(void)
+static void nmi_raise_cpu_backtrace(cpumask_t *mask)
 {
-	int i;
-
-	if (test_and_set_bit(0, &backtrace_flag))
-		/*
-		 * If there is already a trigger_all_cpu_backtrace() in progress
-		 * (backtrace_flag == 1), don't output double cpu dump infos.
-		 */
-		return;
-
-	cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
-
-	printk(KERN_INFO "sending NMI to all CPUs:\n");
-	apic->send_IPI_all(NMI_VECTOR);
-
-	/* Wait for up to 10 seconds for all CPUs to do the backtrace */
-	for (i = 0; i < 10 * 1000; i++) {
-		if (cpumask_empty(to_cpumask(backtrace_mask)))
-			break;
-		mdelay(1);
-	}
+	apic->send_IPI_mask(mask, NMI_VECTOR);
+}
 
-	clear_bit(0, &backtrace_flag);
-	smp_mb__after_clear_bit();
+void arch_trigger_all_cpu_backtrace(bool include_self)
+{
+	nmi_trigger_all_cpu_backtrace(include_self, nmi_raise_cpu_backtrace);
 }
 
-static int __kprobes
+static int
 arch_trigger_all_cpu_backtrace_handler(unsigned int cmd, struct pt_regs *regs)
 {
-	int cpu;
-
-	cpu = smp_processor_id();
-
-	if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
-		static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
-
-		arch_spin_lock(&lock);
-		printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
-		show_regs(regs);
-		arch_spin_unlock(&lock);
-		cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
+	if (nmi_cpu_backtrace(regs))
 		return NMI_HANDLED;
-	}
 
 	return NMI_DONE;
 }
+NOKPROBE_SYMBOL(arch_trigger_all_cpu_backtrace_handler);
 
 static int __init register_trigger_all_cpu_backtrace(void)
 {