fuzz: fix least request LB maximal active_request_bias value (envoypr…

…oxy#33245) * fuzz: fix least request LB maximal active_request_bias value The default_value of the active_request_bias config field can be high, which will end up setting the weight value in this line (1.0 / 2^active_request_bias) to essentially make all weights 0. This PR adds a check to avoid setting this value to more than 25 in the fuzz tests. Signed-off-by: Adi Suissa-Peleg <[email protected]>
fredyw · Apr 2, 2024 · 3a26f5a · 3a26f5a
1 parent d92decb
commit 3a26f5a
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diff --git a/test/common/upstream/least_request_load_balancer_corpus/large_active_request_bias b/test/common/upstream/least_request_load_balancer_corpus/large_active_request_bias
diff --git a/test/common/upstream/least_request_load_balancer_fuzz_test.cc b/test/common/upstream/least_request_load_balancer_fuzz_test.cc
@@ -53,11 +53,22 @@ DEFINE_PROTO_FUZZER(const test::common::upstream::LeastRequestLoadBalancerTestCa
                    MaxChoiceCountForTest);
     return;
   }
-  // Validate the correctness of the Slow-Start config values.
-  if (input.has_least_request_lb_config() &&
-      input.least_request_lb_config().has_slow_start_config()) {
-    if (!ZoneAwareLoadBalancerFuzzBase::validateSlowStart(
-            input.least_request_lb_config().slow_start_config())) {
+  if (input.has_least_request_lb_config()) {
+    const auto& least_request_lb_config = input.least_request_lb_config();
+    // Validate the correctness of the Slow-Start config values.
+    if (least_request_lb_config.has_slow_start_config() &&
+        !ZoneAwareLoadBalancerFuzzBase::validateSlowStart(
+            least_request_lb_config.slow_start_config())) {
+      return;
+    }
+    // Validate that the active_request_bias is not too large (or else it will
+    // effectively zero all the weights).
+    if (least_request_lb_config.has_active_request_bias() &&
+        least_request_lb_config.active_request_bias().default_value() > 25) {
+      ENVOY_LOG_MISC(debug,
+                     "active_request_bias default_value in the least-request config is too high "
+                     "({} > 25), skipping test as the config is invalid",
+                     least_request_lb_config.active_request_bias().default_value());
       return;
     }
   }