The patch titled
s390: next_timer_interrupt overflow in stop_hz_timer
has been added to the -mm tree. Its filename is
s390-next_timer_interrupt-overflow-in-stop_hz_timer.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: s390: next_timer_interrupt overflow in stop_hz_timer
From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
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@xxxxxxxxxx>)
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/s390/kernel/time.c | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)
diff -puN arch/s390/kernel/time.c~s390-next_timer_interrupt-overflow-in-stop_hz_timer arch/s390/kernel/time.c
--- devel/arch/s390/kernel/time.c~s390-next_timer_interrupt-overflow-in-stop_hz_timer 2006-05-19 02:31:36.000000000 -0700
+++ devel-akpm/arch/s390/kernel/time.c 2006-05-19 02:31:36.000000000 -0700
@@ -272,7 +272,7 @@ static inline void stop_hz_timer(void)
next = next_timer_interrupt();
do {
seq = read_seqbegin_irqsave(&xtime_lock, flags);
- timer = (__u64)(next - jiffies) + jiffies_64;
+ timer = (__u64 next) - (__u64 jiffies) + jiffies_64;
} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
todval = -1ULL;
/* Be careful about overflows. */
_
Patches currently in -mm which might be from schwidefsky@xxxxxxxxxx are
origin.patch
fix-a-no_idle_hz-timer-bug.patch
s390-next_timer_interrupt-overflow-in-stop_hz_timer.patch
create-sys-hypervisor-when-needed.patch
s390_hypfs-filesystem.patch
s390-statistics-infrastructure.patch
adjust-handle_irr_event-return-type.patch
define-__raw_get_cpu_var-and-use-it.patch
-
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