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time: Move ktime_t overflow checking into timespec_valid_strict

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commit cee58483cf upstream

Andreas Bombe reported that the added ktime_t overflow checking added to
timespec_valid in commit 4e8b14526c ("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@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>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
John Stultz
2012-09-11 20:49:53 -04:00
committed by Greg Kroah-Hartman
parent 4ffa9a8069
commit fe979e2c0a
2 changed files with 17 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
include/linux/time.h
View File

@@ -125,6 +125,13 @@ static inline bool timespec_valid(const struct timespec *ts)
/* 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;

14
kernel/time/timekeeping.c
View File

@@ -382,7 +382,7 @@ int do_settimeofday(const struct timespec *tv)
struct timespec ts_delta;
unsigned long flags;
if (!timespec_valid(tv))
if (!timespec_valid_strict(tv))
return -EINVAL;
write_seqlock_irqsave(&xtime_lock, flags);
@@ -428,7 +428,7 @@ int timekeeping_inject_offset(struct timespec *ts)
timekeeping_forward_now();
tmp = timespec_add(xtime, *ts);
if (!timespec_valid(&tmp)) {
if (!timespec_valid_strict(&tmp)) {
ret = -EINVAL;
goto error;
}
@@ -591,7 +591,7 @@ 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;
@@ -599,7 +599,7 @@ 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;
@@ -649,6 +649,12 @@ static void update_sleep_time(struct timespec t)
*/
static void __timekeeping_inject_sleeptime(struct timespec *delta)
{
if (!timespec_valid_strict(delta)) {
printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid "
"sleep delta value!\n");
return;
}
xtime = timespec_add(xtime, *delta);
wall_to_monotonic = timespec_sub(wall_to_monotonic, *delta);
update_sleep_time(timespec_add(total_sleep_time, *delta));