Re: [PATCH] softlockup: stop spurious softlockup messages due to overflow

[Colin Ian King <colin.king@canonical.com>]

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Re-submitted, thanks for you feedback.

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>From d640e08bfba1abdd1a82f0f11cbde62f29b3f423 Mon Sep 17 00:00:00 2001
From: Colin Ian King <colin.king@canonical.com>
Date: Fri, 19 Mar 2010 10:17:03 +0000
Subject: [PATCH] softlockup: stop spurious softlockup messages due to overflow

Ensure additions on touch_ts do not overflow.  This can occur when
the top 32 bits of the TSC reach 0xffffffff causing additions to
touch_ts to overflow and this in turn generates spurious softlockup
warnings.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: stable@kernel.org
---
 kernel/softlockup.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/softlockup.c b/kernel/softlockup.c
index 0d4c789..4b493f6 100644
--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -155,11 +155,11 @@ void softlockup_tick(void)
 	 * Wake up the high-prio watchdog task twice per
 	 * threshold timespan.
 	 */
-	if (now > touch_ts + softlockup_thresh/2)
+	if (time_after(now - softlockup_thresh/2, touch_ts))
 		wake_up_process(per_cpu(softlockup_watchdog, this_cpu));
 
 	/* Warn about unreasonable delays: */
-	if (now <= (touch_ts + softlockup_thresh))
+	if (time_before_eq(now - softlockup_thresh, touch_ts))
 		return;
 
 	per_cpu(softlockup_print_ts, this_cpu) = touch_ts;
-- 
1.6.3.3