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[tip:timers/urgent] clocksource: Fix abs() usage w/ 64bit values

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  [tip:timers/urgent] clocksource: Fix abs() usage w/ 64bit values tip-bot for John Stultz <tipbot@zytor.com> - 2015-10-02 23:00 +0200

#1238613 — [tip:timers/urgent] clocksource: Fix abs() usage w/ 64bit values

Commit-ID:  67dfae0cd72fec5cd158b6e5fb1647b7dbe0834c
Gitweb:     http://git.kernel.org/tip/67dfae0cd72fec5cd158b6e5fb1647b7dbe0834c
Author:     John Stultz <john.stultz@linaro.org>
AuthorDate: Mon, 14 Sep 2015 18:05:20 -0700
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 2 Oct 2015 22:53:01 +0200

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

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().

Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1442279124-7309-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/time/clocksource.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 841b72f..3a38775 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -217,7 +217,7 @@ static void clocksource_watchdog(unsigned long data)
 			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",
--
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