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-rw-r--r--include/linux/ktime.h7
-rw-r--r--kernel/time/hrtimer.c2
2 files changed, 8 insertions, 1 deletions
diff --git a/include/linux/ktime.h b/include/linux/ktime.h
index 2b6a204bd8d4..3ffc69ebe967 100644
--- a/include/linux/ktime.h
+++ b/include/linux/ktime.h
@@ -64,6 +64,13 @@ static inline ktime_t ktime_set(const s64 secs, const unsigned long nsecs)
({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
/*
+ * Same as ktime_add(), but avoids undefined behaviour on overflow; however,
+ * this means that you must check the result for overflow yourself.
+ */
+#define ktime_add_unsafe(lhs, rhs) \
+ ({ (ktime_t){ .tv64 = (u64) (lhs).tv64 + (rhs).tv64 }; })
+
+/*
* Add a ktime_t variable and a scalar nanosecond value.
* res = kt + nsval:
*/
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 17f7bcff1e02..1dc94768b5a3 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -312,7 +312,7 @@ EXPORT_SYMBOL_GPL(__ktime_divns);
*/
ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
{
- ktime_t res = ktime_add(lhs, rhs);
+ ktime_t res = ktime_add_unsafe(lhs, rhs);
/*
* We use KTIME_SEC_MAX here, the maximum timeout which we can