linux-kernel - [PATCH] clocksource: really use a margin of 12.5% to limit deferment

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <1291306126-16990-1-git-send-email-u.kleine-koenig@pengutronix.de>
Date:	Thu,  2 Dec 2010 17:08:46 +0100
From:	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
To:	linux-kernel@...r.kernel.org
Cc:	Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH] clocksource: really use a margin of 12.5% to limit deferment

< ukleinek> tglx: the last comment in clocksource_max_deferment is wrong I
            think.  Unless I'm mistaken the margin is only 2^-5, not 2^-3
< ukleinek> i.e. 3.125%, not 12.5%
...
< tglx> crap, the 3.125% is a bit narrow

So fix the code to really do what the comment specifies.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
---
 kernel/time/clocksource.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index c18d7ef..0ddf372 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -528,7 +528,7 @@ static u64 clocksource_max_deferment(struct clocksource *cs)
 	 * note a margin of 12.5% is used because this can be computed with
 	 * a shift, versus say 10% which would require division.
 	 */
-	return max_nsecs - (max_nsecs >> 5);
+	return max_nsecs - (max_nsecs >> 3);
 }
 
 #ifndef CONFIG_ARCH_USES_GETTIMEOFFSET
-- 
1.7.2.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/