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Commit c24ce1d8 authored by Linus Torvalds's avatar Linus Torvalds
Browse files
* git://git.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt:
  hrtimer: catch expired CLOCK_REALTIME timers early
  hrtimer: check relative timeouts for overflow
parents f527cf40 63070a79
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+2 −0
Original line number Diff line number Diff line
@@ -310,6 +310,8 @@ static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
	return ktime_sub_ns(kt, usec * 1000);
}

extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);

/*
 * The resolution of the clocks. The resolution value is returned in
 * the clock_getres() system call to give application programmers an
+1 −1
Original line number Diff line number Diff line
@@ -2116,7 +2116,7 @@ asmlinkage long sys_futex(u32 __user *uaddr, int op, u32 val,

		t = timespec_to_ktime(ts);
		if (cmd == FUTEX_WAIT)
			t = ktime_add(ktime_get(), t);
			t = ktime_add_safe(ktime_get(), t);
		tp = &t;
	}
	/*
+1 −1
Original line number Diff line number Diff line
@@ -176,7 +176,7 @@ asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,

		t = timespec_to_ktime(ts);
		if (cmd == FUTEX_WAIT)
			t = ktime_add(ktime_get(), t);
			t = ktime_add_safe(ktime_get(), t);
		tp = &t;
	}
	if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE)
+31 −17
Original line number Diff line number Diff line
@@ -325,6 +325,23 @@ u64 ktime_divns(const ktime_t kt, s64 div)
}
#endif /* BITS_PER_LONG >= 64 */

/*
 * Add two ktime values and do a safety check for overflow:
 */
ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
{
	ktime_t res = ktime_add(lhs, rhs);

	/*
	 * We use KTIME_SEC_MAX here, the maximum timeout which we can
	 * return to user space in a timespec:
	 */
	if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
		res = ktime_set(KTIME_SEC_MAX, 0);

	return res;
}

/*
 * Check, whether the timer is on the callback pending list
 */
@@ -425,6 +442,8 @@ static int hrtimer_reprogram(struct hrtimer *timer,
	ktime_t expires = ktime_sub(timer->expires, base->offset);
	int res;

	WARN_ON_ONCE(timer->expires.tv64 < 0);

	/*
	 * When the callback is running, we do not reprogram the clock event
	 * device. The timer callback is either running on a different CPU or
@@ -435,6 +454,15 @@ static int hrtimer_reprogram(struct hrtimer *timer,
	if (hrtimer_callback_running(timer))
		return 0;

	/*
	 * CLOCK_REALTIME timer might be requested with an absolute
	 * expiry time which is less than base->offset. Nothing wrong
	 * about that, just avoid to call into the tick code, which
	 * has now objections against negative expiry values.
	 */
	if (expires.tv64 < 0)
		return -ETIME;

	if (expires.tv64 >= expires_next->tv64)
		return 0;

@@ -682,13 +710,7 @@ u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
		 */
		orun++;
	}
	timer->expires = ktime_add(timer->expires, interval);
	/*
	 * Make sure, that the result did not wrap with a very large
	 * interval.
	 */
	if (timer->expires.tv64 < 0)
		timer->expires = ktime_set(KTIME_SEC_MAX, 0);
	timer->expires = ktime_add_safe(timer->expires, interval);

	return orun;
}
@@ -839,7 +861,7 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
	new_base = switch_hrtimer_base(timer, base);

	if (mode == HRTIMER_MODE_REL) {
		tim = ktime_add(tim, new_base->get_time());
		tim = ktime_add_safe(tim, new_base->get_time());
		/*
		 * CONFIG_TIME_LOW_RES is a temporary way for architectures
		 * to signal that they simply return xtime in
@@ -848,16 +870,8 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
		 * timeouts. This will go away with the GTOD framework.
		 */
#ifdef CONFIG_TIME_LOW_RES
		tim = ktime_add(tim, base->resolution);
		tim = ktime_add_safe(tim, base->resolution);
#endif
		/*
		 * Careful here: User space might have asked for a
		 * very long sleep, so the add above might result in a
		 * negative number, which enqueues the timer in front
		 * of the queue.
		 */
		if (tim.tv64 < 0)
			tim.tv64 = KTIME_MAX;
	}
	timer->expires = tim;

+5 −3
Original line number Diff line number Diff line
@@ -767,9 +767,11 @@ common_timer_set(struct k_itimer *timr, int flags,
	/* SIGEV_NONE timers are not queued ! See common_timer_get */
	if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) {
		/* Setup correct expiry time for relative timers */
		if (mode == HRTIMER_MODE_REL)
			timer->expires = ktime_add(timer->expires,
		if (mode == HRTIMER_MODE_REL) {
			timer->expires =
				ktime_add_safe(timer->expires,
					       timer->base->get_time());
		}
		return 0;
	}