[PATCH] fix vsyscall settimeofday

From: Daniel Walker
Date: Mon Mar 05 2007 - 11:58:57 EST


I've only seen this on x86_64 .

The vsyscall state only gets updated when a timer interrupts comes in . So
if the time is set long before the next timer, there will be a period when
a gettimeofday() won't reflect the correct time.

I added an explicit update_vsyscall() during the settimeofday(), that way
the vsyscall state doesn't get stale.

Any thought John?

Signed-Off-By: Daniel Walker <dwalker@xxxxxxxxxx>

---
kernel/timer.c | 2 ++
1 file changed, 2 insertions(+)

Index: linux-2.6.20/kernel/timer.c
===================================================================
--- linux-2.6.20.orig/kernel/timer.c
+++ linux-2.6.20/kernel/timer.c
@@ -861,6 +861,8 @@ int do_settimeofday(struct timespec *tv)
clock->error = 0;
ntp_clear();

+ update_vsyscall(&xtime, clock);
+
write_sequnlock_irqrestore(&xtime_lock, flags);

/* signal hrtimers about time change */
--
-
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