1 files changed, 21 insertions, 6 deletions

diff --git a/include/linux/ktime.h b/include/linux/ktime.h
index 5fc3d1083071..2b6a204bd8d4 100644
--- a/include/linux/ktime.h
+++ b/include/linux/ktime.h
@@ -166,19 +166,34 @@ static inline bool ktime_before(const ktime_t cmp1, const ktime_t cmp2)
 }
 
 #if BITS_PER_LONG < 64
-extern u64 __ktime_divns(const ktime_t kt, s64 div);
-static inline u64 ktime_divns(const ktime_t kt, s64 div)
+extern s64 __ktime_divns(const ktime_t kt, s64 div);
+static inline s64 ktime_divns(const ktime_t kt, s64 div)
 {
+        /*
+         * Negative divisors could cause an inf loop,
+         * so bug out here.
+         */
+        BUG_ON(div < 0);
         if (__builtin_constant_p(div) && !(div >> 32)) {
-                u64 ns = kt.tv64;
-                do_div(ns, div);
-                return ns;
+                s64 ns = kt.tv64;
+                u64 tmp = ns < 0 ? -ns : ns;
+
+                do_div(tmp, div);
+                return ns < 0 ? -tmp : tmp;
         } else {
                 return __ktime_divns(kt, div);
         }
 }
 #else /* BITS_PER_LONG < 64 */
-# define ktime_divns(kt, div)           (u64)((kt).tv64 / (div))
+static inline s64 ktime_divns(const ktime_t kt, s64 div)
+{
+        /*
+         * 32-bit implementation cannot handle negative divisors,
+         * so catch them on 64bit as well.
+         */
+        WARN_ON(div < 0);
+        return kt.tv64 / div;
+}
 #endif
 
 static inline s64 ktime_to_us(const ktime_t kt)