From: john stultz Date: Mon, 21 May 2007 12:31:52 +0000 (+0200) Subject: x86_64: vsyscall time() fix X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=d0aff6e6f4e54f79f9c89d147d371bad384454e9;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git x86_64: vsyscall time() fix The vsyscall time() function basically returns the second portion of xtime directly. This however means that there is about a ticks worth of time each second where time() will return a second value less then what gettimeofday() does. Additionally, this window where vtime() is behind vgettimeofday() grows when dynticks is enabled, so its probably good to get this in before dynticks lands. Big thanks to Sripathi for noticing this issue and creating a test case to work with! This patch changes the vtime() implemenation to call vgettimeofday(), much as syscall time() implementation calls gettimeofday(). 2.6.21 stable candidate too Signed-off-by: John Stultz Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- diff --git a/arch/x86_64/kernel/vsyscall.c b/arch/x86_64/kernel/vsyscall.c index 51d4c6fa88c8..57660d58d500 100644 --- a/arch/x86_64/kernel/vsyscall.c +++ b/arch/x86_64/kernel/vsyscall.c @@ -175,10 +175,13 @@ int __vsyscall(0) vgettimeofday(struct timeval * tv, struct timezone * tz) * unlikely */ time_t __vsyscall(1) vtime(time_t *t) { + struct timeval tv; time_t result; if (unlikely(!__vsyscall_gtod_data.sysctl_enabled)) return time_syscall(t); - result = __vsyscall_gtod_data.wall_time_sec; + + vgettimeofday(&tv, 0); + result = tv.tv_sec; if (t) *t = result; return result;