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timekeeping: Fix timezone update

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commit 64ce4c2f (time: Clean up warp_clock()) breaks the timezone
update in a very subtle way. To avoid the direct access to timekeeping
internals it adds the timezone delta to the current time with
timespec_add_safe(). This works nicely when the timezone delta is > 0.
If timezone delta is < 0 then the wrap check in timespec_add_safe()
triggers and timespec_add_safe() returns TIME_MAX and screws up
timekeeping completely. 

The comment above timespec_add_safe() says:
    It's assumed that both values are valid (>= 0)

Add the timezone seconds adjustment directly.

Reported-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2010-05-23 08:14:45 +02:00
parent f4b87dee92
commit bd45b7a385
1 changed files with 4 additions and 4 deletions
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8
kernel/time.c
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@ -132,10 +132,10 @@ SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv,
*/ */
static inline void warp_clock(void) static inline void warp_clock(void)
{ {
struct timespec delta, adjust; struct timespec adjust;
delta.tv_sec = sys_tz.tz_minuteswest * 60;
delta.tv_nsec = 0; adjust = current_kernel_time();
adjust = timespec_add_safe(current_kernel_time(), delta); adjust.tv_sec += sys_tz.tz_minuteswest * 60;
do_settimeofday(&adjust); do_settimeofday(&adjust);
} }