fix the softlockup watchdog to actually work

patch a115d5caca1a2905ba7a32b408a6042b20179aaa in mainline.

this Xen related commit:

   commit 966812dc98e6a7fcdf759cbfa0efab77500a8868
   Author: Jeremy Fitzhardinge <jeremy@goop.org>
   Date:   Tue May 8 00:28:02 2007 -0700

       Ignore stolen time in the softlockup watchdog

broke the softlockup watchdog to never report any lockups. (!)

print_timestamp defaults to 0, this makes the following condition
always true:

	if (print_timestamp < (touch_timestamp + 1) ||

and we'll in essence never report soft lockups.

apparently the functionality of the soft lockup watchdog was never
actually tested with that patch applied ...

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index 708d4882c0c391bffa47a24ae0153bccabd0a1c7..e557c44b127584956cc50044ba49776aa59a8959 100644 (file)
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -80,10 +80,11 @@ void softlockup_tick(void)
        print_timestamp = per_cpu(print_timestamp, this_cpu);
 
        /* report at most once a second */
-       if (print_timestamp < (touch_timestamp + 1) ||
-               did_panic ||
-                       !per_cpu(watchdog_task, this_cpu))
+       if ((print_timestamp >= touch_timestamp &&
+                       print_timestamp < (touch_timestamp + 1)) ||
+                       did_panic || !per_cpu(watchdog_task, this_cpu)) {
                return;
+       }
 
        /* do not print during early bootup: */
        if (unlikely(system_state != SYSTEM_RUNNING)) {