From: Thomas Gleixner Date: Sun, 23 May 2010 06:14:45 +0000 (+0200) Subject: timekeeping: Fix timezone update X-Git-Tag: v2.6.35-rc1~413^2~1 X-Git-Url: http://git.samba.org/samba.git/?p=sfrench%2Fcifs-2.6.git;a=commitdiff_plain;h=bd45b7a385c5ffd82c11a1d51880be18559e5ad9 timekeeping: Fix timezone update 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 Tested-by: Rafael J. Wysocki Acked-by: John Stultz Signed-off-by: Thomas Gleixner --- diff --git a/kernel/time.c b/kernel/time.c index 50612faa9baf..848b1c2ab09a 100644 --- a/kernel/time.c +++ b/kernel/time.c @@ -132,10 +132,10 @@ SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv, */ static inline void warp_clock(void) { - struct timespec delta, adjust; - delta.tv_sec = sys_tz.tz_minuteswest * 60; - delta.tv_nsec = 0; - adjust = timespec_add_safe(current_kernel_time(), delta); + struct timespec adjust; + + adjust = current_kernel_time(); + adjust.tv_sec += sys_tz.tz_minuteswest * 60; do_settimeofday(&adjust); }