net_sched: gen_estimator: fix broken estimators based on percpu stats

[ Upstream commit a5f7add332b4ea6d4b9480971b3b0f5e66466ae9 ]

pfifo_fast got percpu stats lately, uncovering a bug I introduced last
year in linux-4.10.

I missed the fact that we have to clear our temporary storage
before calling __gnet_stats_copy_basic() in the case of percpu stats.

Without this fix, rate estimators (tc qd replace dev xxx root est 1sec
4sec pfifo_fast) are utterly broken.

Fixes: 1c0d32fde5bd ("net_sched: gen_estimator: complete rewrite of rate estimators")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index 00ecec4891f3835c7512e93f0b8551fe6f0095a1..7f980bd7426ea0c771f920b4381de16ff0ea06b6 100644 (file)
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -66,6 +66,7 @@ struct net_rate_estimator {
 static void est_fetch_counters(struct net_rate_estimator *e,
                               struct gnet_stats_basic_packed *b)
 {
+       memset(b, 0, sizeof(*b));
        if (e->stats_lock)
                spin_lock(e->stats_lock);