/* Locks kprobe: irqs must be disabled */
void __kprobes lock_kprobes(void)
{
+ unsigned long flags = 0;
+
+ /* Avoiding local interrupts to happen right after we take the kprobe_lock
+ * and before we get a chance to update kprobe_cpu, this to prevent
+ * deadlock when we have a kprobe on ISR routine and a kprobe on task
+ * routine
+ */
+ local_irq_save(flags);
+
spin_lock(&kprobe_lock);
kprobe_cpu = smp_processor_id();
+
+ local_irq_restore(flags);
}
void __kprobes unlock_kprobes(void)
{
+ unsigned long flags = 0;
+
+ /* Avoiding local interrupts to happen right after we update
+ * kprobe_cpu and before we get a a chance to release kprobe_lock,
+ * this to prevent deadlock when we have a kprobe on ISR routine and
+ * a kprobe on task routine
+ */
+ local_irq_save(flags);
+
kprobe_cpu = NR_CPUS;
spin_unlock(&kprobe_lock);
+
+ local_irq_restore(flags);
}
/* You have to be holding the kprobe_lock */