From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Sat, 20 May 2006 22:00:25 +0000 (-0700)
Subject: [PATCH] s390: next_timer_interrupt overflow in stop_hz_timer
X-Git-Tag: v2.6.17-rc5~43
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=92f63cd000059366af18712367216d96180e0ec0;p=pandora-kernel.git

[PATCH] s390: next_timer_interrupt overflow in stop_hz_timer

The 32 bit unsigned substraction (next - jiffies) in stop_hz_timer can
overflow if jiffies gets advanced between next_timer_interrupt and the read
under the xtime lock.  The cast to a u64 then results in a large value
which causes the cpu to wait too long.  Fix this by casting next and
jiffies independently to u64 before subtracting them.

(Spotted by Zachary Amsden <zach@vmware.com>)

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

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