[PARISC] Fix do_gettimeofday() hang

[linux-2.6] / arch / parisc / kernel / time.c

diff --git a/arch/parisc/kernel/time.c b/arch/parisc/kernel/time.c
index cded2568078741c3177f56b23ef64a3e4a9d2488..eb35e1c0bb532b679b660351fc5e28db1e6ee8b8 100644 (file)
--- a/arch/parisc/kernel/time.c
+++ b/arch/parisc/kernel/time.c
@@ -36,8 +36,8 @@
 /* xtime and wall_jiffies keep wall-clock time */
 extern unsigned long wall_jiffies;
 
-static long clocktick; /* timer cycles per tick */
-static long halftick;
+static long clocktick __read_mostly;   /* timer cycles per tick */
+static long halftick __read_mostly;
 
 #ifdef CONFIG_SMP
 extern void smp_do_timer(struct pt_regs *regs);
@@ -157,8 +157,22 @@ do_gettimeofday (struct timeval *tv)
                usec += (xtime.tv_nsec / 1000);
        } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 
-       while (usec >= 1000000) {
-               usec -= 1000000;
+       if (unlikely(usec > LONG_MAX)) {
+               /* This can happen if the gettimeoffset adjustment is
+                * negative and xtime.tv_nsec is smaller than the
+                * adjustment */
+               printk(KERN_ERR "do_gettimeofday() spurious xtime.tv_nsec of %ld\n", usec);
+               usec += USEC_PER_SEC;
+               --sec;
+               /* This should never happen, it means the negative
+                * time adjustment was more than a second, so there's
+                * something seriously wrong */
+               BUG_ON(usec > LONG_MAX);
+       }
+
+
+       while (usec >= USEC_PER_SEC) {
+               usec -= USEC_PER_SEC;
                ++sec;
        }