[ 188/218] time: Move ktime_t overflow checking into timespec_valid_strict

From: Greg Kroah-Hartman
Date: Fri Sep 28 2012 - 16:31:56 EST


3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: John Stultz <john.stultz@xxxxxxxxxx>

commit cee58483cf56e0ba355fdd97ff5e8925329aa936 upstream

Andreas Bombe reported that the added ktime_t overflow checking added to
timespec_valid in commit 4e8b14526ca7 ("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: Andreas Bombe <aeb@xxxxxxxxxx>
Cc: Zhouping Liu <zliu@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/time.h | 7 +++++++
kernel/time/timekeeping.c | 10 +++++-----
2 files changed, 12 insertions(+), 5 deletions(-)

--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -125,6 +125,13 @@ static inline bool timespec_valid(const
/* Can't have more nanoseconds then a second */
if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
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 */
if ((unsigned long long)ts->tv_sec >= KTIME_SEC_MAX)
return false;
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -385,7 +385,7 @@ int do_settimeofday(const struct timespe
struct timespec ts_delta;
unsigned long flags;

- if (!timespec_valid(tv))
+ if (!timespec_valid_strict(tv))
return -EINVAL;

write_seqlock_irqsave(&timekeeper.lock, flags);
@@ -431,7 +431,7 @@ int timekeeping_inject_offset(struct tim
timekeeping_forward_now();

tmp = timespec_add(timekeeper.xtime, *ts);
- if (!timespec_valid(&tmp)) {
+ if (!timespec_valid_strict(&tmp)) {
ret = -EINVAL;
goto error;
}
@@ -608,7 +608,7 @@ void __init timekeeping_init(void)
struct timespec now, boot;

read_persistent_clock(&now);
- if (!timespec_valid(&now)) {
+ if (!timespec_valid_strict(&now)) {
pr_warn("WARNING: Persistent clock returned invalid value!\n"
" Check your CMOS/BIOS settings.\n");
now.tv_sec = 0;
@@ -616,7 +616,7 @@ void __init timekeeping_init(void)
}

read_boot_clock(&boot);
- if (!timespec_valid(&boot)) {
+ if (!timespec_valid_strict(&boot)) {
pr_warn("WARNING: Boot clock returned invalid value!\n"
" Check your CMOS/BIOS settings.\n");
boot.tv_sec = 0;
@@ -667,7 +667,7 @@ static void update_sleep_time(struct tim
*/
static void __timekeeping_inject_sleeptime(struct timespec *delta)
{
- if (!timespec_valid(delta)) {
+ if (!timespec_valid_strict(delta)) {
printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid "
"sleep delta value!\n");
return;


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/