1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/dahdi/dahdi-base.c b/drivers/dahdi/dahdi-base.c
index 511f9c1..2c6fc0d 100644
--- a/drivers/dahdi/dahdi-base.c
+++ b/drivers/dahdi/dahdi-base.c
@@ -8144,6 +8144,7 @@ static void coretimer_func(unsigned long param)
 	const unsigned long MAX_INTERVAL = 100000L;
 	const unsigned long FOURMS_INTERVAL = HZ/250;
 	const unsigned long ONESEC_INTERVAL = HZ;
+	const unsigned long MS_LIMIT = 3000;
 
 	now = current_kernel_time();
 
@@ -8158,6 +8159,23 @@ static void coretimer_func(unsigned long param)
 			mod_timer(&core_timer.timer, jiffies + FOURMS_INTERVAL);
 
 		ms_since_start = core_diff_ms(&core_timer.start_interval, &now);
+
+		/*
+		 * If the system time has changed, it is possible for us to be
+		 * far behind.  If we are more than MS_LIMIT milliseconds
+		 * behind, just reset our time base and continue so that we do
+		 * not hang the system here.
+		 *
+		 */
+		if (unlikely((ms_since_start - atomic_read(&core_timer.count)) > MS_LIMIT)) {
+			if (printk_ratelimit())
+				module_printk(KERN_INFO, "Detected time shift.\n");
+			atomic_set(&core_timer.count, 0);
+			atomic_set(&core_timer.last_count, 0);
+			core_timer.start_interval = now;
+			return;
+		}
+
 		while (ms_since_start > atomic_read(&core_timer.count))
 			process_masterspan();