ktime_add_safe would check for overflows, but since ktime variables are signed, overflowing them is an undefined behaviour and should be avoided.
Rather than checking for wraparound after the overflow, check for potential overflowing values prior to adding both ktimes. Signed-off-by: Sasha Levin <[email protected]> --- kernel/time/hrtimer.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 37e50aa..42fb631 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -290,16 +290,14 @@ 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); - /* * 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); + if (lhs.tv64 > (KTIME_MAX - rhs.tv64)) + return ktime_set(KTIME_SEC_MAX, 0); - return res; + return ktime_add(lhs, rhs); } EXPORT_SYMBOL_GPL(ktime_add_safe); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
