diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index 80dbf2f4016e..8e582e29a41e 100644
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -80,11 +80,11 @@ static void est_timer(struct timer_list *t)
 	u64 rate, brate;
 
 	est_fetch_counters(est, &b);
-	brate = (b.bytes - est->last_bytes) << (10 - est->ewma_log - est->intvl_log);
-	brate -= (est->avbps >> est->ewma_log);
+	brate = (b.bytes - est->last_bytes) << (10 - est->intvl_log);
+	brate = (brate >> est->ewma_log) - (est->avbps >> est->ewma_log);
 
-	rate = (b.packets - est->last_packets) << (10 - est->ewma_log - est->intvl_log);
-	rate -= (est->avpps >> est->ewma_log);
+	rate = (b.packets - est->last_packets) << (10 - est->intvl_log);
+	rate = (rate >> est->ewma_log) - (est->avpps >> est->ewma_log);
 
 	write_seqcount_begin(&est->seq);
 	est->avbps += brate;
@@ -143,6 +143,9 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
 	if (parm->interval < -2 || parm->interval > 3)
 		return -EINVAL;
 
+	if (parm->ewma_log == 0 || parm->ewma_log >= 31)
+		return -EINVAL;
+
 	est = kzalloc(sizeof(*est), GFP_KERNEL);
 	if (!est)
 		return -ENOBUFS;