--- /usr/src/linux-2.4.3/fs/proc/proc_misc.c	Sun Aug 26 23:14:49 2001
+++ /usr/src/linux-2.4.3-test/fs/proc/proc_misc.c	Mon Aug 27 20:21:19 2001
@@ -13,6 +13,14 @@
  * Changes:
  * Fulton Green      :  Encapsulated position metric calculations.
  *			<kernel@FultonGreen.com>
+ *
+ * Frank Schneider   :  Fixed Uptime-Bug resetting /proc/uptime
+ *                      after 497 days, 2h:27m:52.96sec to zero
+ *                      due to overflow in "jiffies".
+ *                      Tested only on i386.
+ *                      FIXME: Port this fix to non-intel.
+ *                      <spatz1@t-online.de>
+ *
  */
 
 #include <linux/types.h>
@@ -100,15 +108,68 @@
 	return proc_calc_metrics(page, start, off, count, eof, len);
 }
 
+
 static int uptime_read_proc(char *page, char **start, off_t off,
 				 int count, int *eof, void *data)
 {
 	unsigned long uptime;
 	unsigned long idle;
+
+/*
+Extra-Variables for Uptime-Overflow-Fix
+*/
+	long int test_jiffies;
+	long int test_idle;
+	static int uptime_overflow_correction=0;
+	static int idle_overflow_correction=0;
+	static unsigned long int jiffies_old;
+	static unsigned long int idle_old;
+	unsigned long int my_jiffies;
+	unsigned long int my_idle;
+	const unsigned long int max_int_value=4294967295;
 	int len;
+		
+/* If you want to test the fix, you can add e.g.
+4294937296 to "my_jiffies" and 4294931296 to "my_idle",
+then both overflows will occur 5 Minutes and 6 Minutes
+after boottime and you do not have to wait 497 days...:-)
+*/
+
+	my_jiffies = jiffies;
+	my_idle = init_tasks[0]->times.tms_utime + init_tasks[0]->times.tms_stime;
+	
+	test_jiffies = my_jiffies;
+	test_idle = my_idle;
+	
+	uptime = my_jiffies;
+	idle = my_idle;
+
+/*
+Get values for later comparision.
+*/
+	
+	if (test_jiffies < 0 && jiffies_old == 0)
+		jiffies_old = my_jiffies;
+		
+	if (test_idle < 0 && idle_old == 0)
+		idle_old = my_idle;
+		
+/*
+Check for overflow...
+*/
 
-	uptime = jiffies;
-	idle = init_tasks[0]->times.tms_utime + init_tasks[0]->times.tms_stime;
+	if (my_jiffies < jiffies_old ) {
+		uptime_overflow_correction++;
+		jiffies_old = 0;
+		printk (KERN_NOTICE "Jiffies overflow detected, Uptime-correction enabled!\n");
+		}
+		
+	if (my_idle < idle_old ) {
+		idle_overflow_correction++;
+		idle_old = 0;
+		printk (KERN_NOTICE "Process time of Idletask: Overflow detected, Correction enabled!\n");
+		}
+		
 
 	/* The formula for the fraction parts really is ((t * 100) / HZ) % 100, but
 	   that would overflow about every five days at HZ == 100.
@@ -119,17 +180,27 @@
 	   calculations simplify to the version in the #else part (if the printf
 	   format is adapted to the same number of digits as zeroes in HZ.
 	 */
+
+/* 
+FIXME: Port this fix for intel to other platforms wth HZ!=100
+*/
+
 #if HZ!=100
 	len = sprintf(page,"%lu.%02lu %lu.%02lu\n",
 		uptime / HZ,
 		(((uptime % HZ) * 100) / HZ) % 100,
 		idle / HZ,
 		(((idle % HZ) * 100) / HZ) % 100);
+
+/* 
+Here the correction-values are added to Uptime and Idletime
+*/
+
 #else
 	len = sprintf(page,"%lu.%02lu %lu.%02lu\n",
-		uptime / HZ,
+		uptime / HZ + (uptime_overflow_correction * max_int_value / HZ),
 		uptime % HZ,
-		idle / HZ,
+		idle / HZ + (idle_overflow_correction * max_int_value / HZ),
 		idle % HZ);
 #endif
 	return proc_calc_metrics(page, start, off, count, eof, len);