diff --git a/src/common/hmac.c b/src/common/hmac.c
index 592f9b20a38..a27778e86b3 100644
--- a/src/common/hmac.c
+++ b/src/common/hmac.c
@@ -46,9 +46,7 @@ typedef enum pg_hmac_errno
 	PG_HMAC_ERROR_INTERNAL
 } pg_hmac_errno;
 
-/*
- * Internal structure for pg_hmac_ctx->data with this implementation.
- */
+/* Internal pg_hmac_ctx structure */
 struct pg_hmac_ctx
 {
 	pg_cryptohash_ctx *hash;
diff --git a/src/common/hmac_openssl.c b/src/common/hmac_openssl.c
index c352f9db9e9..44f36d51dcb 100644
--- a/src/common/hmac_openssl.c
+++ b/src/common/hmac_openssl.c
@@ -60,9 +60,7 @@ typedef enum pg_hmac_errno
 	PG_HMAC_ERROR_OPENSSL
 } pg_hmac_errno;
 
-/*
- * Internal structure for pg_hmac_ctx->data with this implementation.
- */
+/* Internal pg_hmac_ctx structure */
 struct pg_hmac_ctx
 {
 	HMAC_CTX   *hmacctx;
diff --git a/src/common/scram-common.c b/src/common/scram-common.c
index 5f90397c66d..8896b1e73e4 100644
--- a/src/common/scram-common.c
+++ b/src/common/scram-common.c
@@ -44,7 +44,10 @@ scram_SaltedPassword(const char *password,
 	pg_hmac_ctx *hmac_ctx = pg_hmac_create(PG_SHA256);
 
 	if (hmac_ctx == NULL)
+	{
+		*errstr = pg_hmac_error(NULL);	/* returns OOM */
 		return -1;
+	}
 
 	/*
 	 * Iterate hash calculation of HMAC entry using given salt.  This is
@@ -126,7 +129,10 @@ scram_ClientKey(const uint8 *salted_password, uint8 *result,
 	pg_hmac_ctx *ctx = pg_hmac_create(PG_SHA256);
 
 	if (ctx == NULL)
+	{
+		*errstr = pg_hmac_error(NULL);	/* returns OOM */
 		return -1;
+	}
 
 	if (pg_hmac_init(ctx, salted_password, SCRAM_KEY_LEN) < 0 ||
 		pg_hmac_update(ctx, (uint8 *) "Client Key", strlen("Client Key")) < 0 ||