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Commit cee58483 authored by John Stultz's avatar John Stultz Committed by Linus Torvalds
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time: Move ktime_t overflow checking into timespec_valid_strict 



Andreas Bombe reported that the added ktime_t overflow checking added to
timespec_valid in commit 4e8b1452 ("time: Improve sanity checking of
timekeeping inputs") was causing problems with X.org because it caused
timeouts larger then KTIME_T to be invalid.

Previously, these large timeouts would be clamped to KTIME_MAX and would
never expire, which is valid.

This patch splits the ktime_t overflow checking into a new
timespec_valid_strict function, and converts the timekeeping codes
internal checking to use this more strict function.

Reported-and-tested-by: default avatarAndreas Bombe <aeb@debian.org>
Cc: Zhouping Liu <zliu@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7a611e69

include/linux/time.h

+7 −0
Original line number Original line Diff line number Diff line
@@ -125,6 +125,13 @@ static inline bool timespec_valid(const struct timespec *ts) 
	/* Can't have more nanoseconds then a second */

	/* Can't have more nanoseconds then a second */

	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)

	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)

		return false;

		return false;

	return true;

}



static inline bool timespec_valid_strict(const struct timespec *ts)

{

	if (!timespec_valid(ts))

		return false;

	/* Disallow values that could overflow ktime_t */

	/* Disallow values that could overflow ktime_t */

	if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)

	if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)

		return false;

		return false;

kernel/time/timekeeping.c

+5 −5
Original line number Original line Diff line number Diff line
@@ -428,7 +428,7 @@ int do_settimeofday(const struct timespec *tv) 
	struct timespec ts_delta, xt;

	struct timespec ts_delta, xt;

	unsigned long flags;

	unsigned long flags;





	if (!timespec_valid(tv))

	if (!timespec_valid_strict(tv))

		return -EINVAL;

		return -EINVAL;





	write_seqlock_irqsave(&tk->lock, flags);

	write_seqlock_irqsave(&tk->lock, flags);
@@ -476,7 +476,7 @@ int timekeeping_inject_offset(struct timespec *ts) 




	/* Make sure the proposed value is valid */

	/* Make sure the proposed value is valid */

	tmp = timespec_add(tk_xtime(tk),  *ts);

	tmp = timespec_add(tk_xtime(tk),  *ts);

	if (!timespec_valid(&tmp)) {

	if (!timespec_valid_strict(&tmp)) {

		ret = -EINVAL;

		ret = -EINVAL;

		goto error;

		goto error;

	}

	}
@@ -659,7 +659,7 @@ void __init timekeeping_init(void) 
	struct timespec now, boot, tmp;

	struct timespec now, boot, tmp;





	read_persistent_clock(&now);

	read_persistent_clock(&now);

	if (!timespec_valid(&now)) {

	if (!timespec_valid_strict(&now)) {

		pr_warn("WARNING: Persistent clock returned invalid value!\n"

		pr_warn("WARNING: Persistent clock returned invalid value!\n"

			"         Check your CMOS/BIOS settings.\n");

			"         Check your CMOS/BIOS settings.\n");

		now.tv_sec = 0;

		now.tv_sec = 0;
@@ -667,7 +667,7 @@ void __init timekeeping_init(void) 
	}

	}





	read_boot_clock(&boot);

	read_boot_clock(&boot);

	if (!timespec_valid(&boot)) {

	if (!timespec_valid_strict(&boot)) {

		pr_warn("WARNING: Boot clock returned invalid value!\n"

		pr_warn("WARNING: Boot clock returned invalid value!\n"

			"         Check your CMOS/BIOS settings.\n");

			"         Check your CMOS/BIOS settings.\n");

		boot.tv_sec = 0;

		boot.tv_sec = 0;
@@ -713,7 +713,7 @@ static struct timespec timekeeping_suspend_time; 
static void __timekeeping_inject_sleeptime(struct timekeeper *tk,

static void __timekeeping_inject_sleeptime(struct timekeeper *tk,

							struct timespec *delta)

							struct timespec *delta)

{

{

	if (!timespec_valid(delta)) {

	if (!timespec_valid_strict(delta)) {

		printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid "

		printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid "

					"sleep delta value!\n");

					"sleep delta value!\n");

		return;

		return;