alarmtimer: Fix bug where relative alarm timers were treated as absolute
Sharvil noticed with the posix timer_settime interface, using the
CLOCK_REALTIME_ALARM or CLOCK_BOOTTIME_ALARM clockid, if the users
tried to specify a relative time timer, it would incorrectly be
treated as absolute regardless of the state of the flags argument.
This patch corrects this, properly checking the absolute/relative flag,
as well as adds further error checking that no invalid flag bits are set.
Reported-by: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Cc: stable <stable@vger.kernel.org> #3.0+
Link: http://lkml.kernel.org/r/1404767171-6902-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 88c9c65..fe75444 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -585,9 +585,14 @@
struct itimerspec *new_setting,
struct itimerspec *old_setting)
{
+ ktime_t exp;
+
if (!rtcdev)
return -ENOTSUPP;
+ if (flags & ~TIMER_ABSTIME)
+ return -EINVAL;
+
if (old_setting)
alarm_timer_get(timr, old_setting);
@@ -597,8 +602,16 @@
/* start the timer */
timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
- alarm_start(&timr->it.alarm.alarmtimer,
- timespec_to_ktime(new_setting->it_value));
+ exp = timespec_to_ktime(new_setting->it_value);
+ /* Convert (if necessary) to absolute time */
+ if (flags != TIMER_ABSTIME) {
+ ktime_t now;
+
+ now = alarm_bases[timr->it.alarm.alarmtimer.type].gettime();
+ exp = ktime_add(now, exp);
+ }
+
+ alarm_start(&timr->it.alarm.alarmtimer, exp);
return 0;
}
@@ -730,6 +743,9 @@
if (!alarmtimer_get_rtcdev())
return -ENOTSUPP;
+ if (flags & ~TIMER_ABSTIME)
+ return -EINVAL;
+
if (!capable(CAP_WAKE_ALARM))
return -EPERM;
