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Patch "clocksource: Fix abs() usage w/ 64bit values" has been added to the 4.2-stable tree

PATCH [email protected] 1 participant 1 message Oct 18, 2015

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This is a note to let you know that I've just added the patch titled

clocksource: Fix abs() usage w/ 64bit values

to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
clocksource-fix-abs-usage-w-64bit-values.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 67dfae0cd72fec5cd158b6e5fb1647b7dbe0834c Mon Sep 17 00:00:00 2001

From: John Stultz <[email protected]>
Date: Mon, 14 Sep 2015 18:05:20 -0700
Subject: clocksource: Fix abs() usage w/ 64bit values

From: John Stultz <[email protected]>

commit 67dfae0cd72fec5cd158b6e5fb1647b7dbe0834c upstream.

This patch fixes one cases where abs() was being used with 64-bit nanosecond values, where the result may be capped at 32-bits.

This potentially could cause watchdog false negatives on 32-bit systems, so this patch addresses the issue by using abs64().

---
 kernel/time/clocksource.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
kernel/time/clocksource.c +1 -1
@@ -217,7 +217,7 @@ static void clocksource_watchdog(unsigne
 			continue;
 
 		/* Check the deviation from the watchdog clocksource. */
-		if ((abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD)) {
+		if (abs64(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) {
 			pr_warn("timekeeping watchdog: Marking clocksource '%s' as unstable because the skew is too large:\n",
 				cs->name);
 			pr_warn("                      '%s' wd_now: %llx wd_last: %llx mask: %llx\n",

Patches currently in stable-queue which might be from [email protected] are

queue-4.2/time-fix-timekeeping_freqadjust-s-incorrect-use-of-abs-instead-of-abs64.patch queue-4.2/clocksource-fix-abs-usage-w-64bit-values.patch