1 files changed, 9 insertions, 2 deletions

diff --git a/src/lib/libcrypto/ecdsa/ecs_lib.c b/src/lib/libcrypto/ecdsa/ecs_lib.c
index e477da430b..814a6bf404 100644
--- a/src/lib/libcrypto/ecdsa/ecs_lib.c
+++ b/src/lib/libcrypto/ecdsa/ecs_lib.c
@@ -200,8 +200,15 @@ ECDSA_DATA *ecdsa_check(EC_KEY *key)
                 ecdsa_data = (ECDSA_DATA *)ecdsa_data_new();
                 if (ecdsa_data == NULL)
                         return NULL;
-                EC_KEY_insert_key_method_data(key, (void *)ecdsa_data,
-                        ecdsa_data_dup, ecdsa_data_free, ecdsa_data_free);
+                data = EC_KEY_insert_key_method_data(key, (void *)ecdsa_data,
+                           ecdsa_data_dup, ecdsa_data_free, ecdsa_data_free);
+                if (data != NULL)
+                        {
+                        /* Another thread raced us to install the key_method
+                         * data and won. */
+                        ecdsa_data_free(ecdsa_data);
+                        ecdsa_data = (ECDSA_DATA *)data;
+                        }
         }
         else
                 ecdsa_data = (ECDSA_DATA *)data;