diff --git a/include/psa/crypto_builtin_composites.h b/include/psa/crypto_builtin_composites.h
index 8000242814..44fa6de4c2 100644
--- a/include/psa/crypto_builtin_composites.h
+++ b/include/psa/crypto_builtin_composites.h
@@ -123,9 +123,6 @@ typedef struct {
     const uint8_t *MBEDTLS_PRIVATE(hash);
     size_t MBEDTLS_PRIVATE(hash_length);
 
-    mbedtls_mpi MBEDTLS_PRIVATE(r);
-    mbedtls_mpi MBEDTLS_PRIVATE(s);
-
 #else
     /* Make the struct non-empty if algs not supported. */
     unsigned MBEDTLS_PRIVATE(dummy);
@@ -138,8 +135,7 @@ typedef struct {
 #if (defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
     defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)) && \
     defined(MBEDTLS_ECP_RESTARTABLE)
-#define MBEDTLS_PSA_SIGN_HASH_INTERRUPTIBLE_OPERATION_INIT { { 0 }, { 0 }, 0, 0, 0, 0, 0, { 0 }, \
-        { 0 } }
+#define MBEDTLS_PSA_SIGN_HASH_INTERRUPTIBLE_OPERATION_INIT { { 0 }, { 0 }, 0, 0, 0, 0, 0 }
 #else
 #define MBEDTLS_PSA_SIGN_HASH_INTERRUPTIBLE_OPERATION_INIT { 0 }
 #endif
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 748cb13f8c..78d8702d07 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -3511,9 +3511,6 @@ psa_status_t mbedtls_psa_sign_hash_start(
 
     mbedtls_ecdsa_restart_init(&operation->restart_ctx);
 
-    mbedtls_mpi_init(&operation->r);
-    mbedtls_mpi_init(&operation->s);
-
     operation->curve_bytes = PSA_BITS_TO_BYTES(
         operation->ctx->grp.pbits);
 
@@ -3547,6 +3544,8 @@ psa_status_t mbedtls_psa_sign_hash_complete(
     size_t *signature_length)
 {
     psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+    mbedtls_mpi r;
+    mbedtls_mpi s;
 
 #if (defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
     defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)) && \
@@ -3556,13 +3555,16 @@ psa_status_t mbedtls_psa_sign_hash_complete(
         return PSA_ERROR_BUFFER_TOO_SMALL;
     }
 
+    mbedtls_mpi_init(&r);
+    mbedtls_mpi_init(&s);
 
     if (PSA_ALG_ECDSA_IS_DETERMINISTIC(operation->alg)) {
+
 #if defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)
         status = mbedtls_to_psa_error(
             mbedtls_ecdsa_sign_det_restartable(&operation->ctx->grp,
-                                               &operation->r,
-                                               &operation->s,
+                                               &r,
+                                               &s,
                                                &operation->ctx->d,
                                                operation->hash,
                                                operation->hash_length,
@@ -3577,8 +3579,8 @@ psa_status_t mbedtls_psa_sign_hash_complete(
 
         status = mbedtls_to_psa_error(
             mbedtls_ecdsa_sign_restartable(&operation->ctx->grp,
-                                           &operation->r,
-                                           &operation->s,
+                                           &r,
+                                           &s,
                                            &operation->ctx->d,
                                            operation->hash,
                                            operation->hash_length,
@@ -3593,7 +3595,7 @@ psa_status_t mbedtls_psa_sign_hash_complete(
         return status;
     } else {
         status =  mbedtls_to_psa_error(
-            mbedtls_mpi_write_binary(&operation->r,
+            mbedtls_mpi_write_binary(&r,
                                      signature,
                                      operation->curve_bytes));
 
@@ -3602,7 +3604,7 @@ psa_status_t mbedtls_psa_sign_hash_complete(
         }
 
         status =  mbedtls_to_psa_error(
-            mbedtls_mpi_write_binary(&operation->s,
+            mbedtls_mpi_write_binary(&s,
                                      signature +
                                      operation->curve_bytes,
                                      operation->curve_bytes));
@@ -3645,9 +3647,6 @@ psa_status_t mbedtls_psa_sign_hash_abort(
 
     mbedtls_ecdsa_restart_free(&operation->restart_ctx);
 
-    mbedtls_mpi_free(&operation->r);
-    mbedtls_mpi_free(&operation->s);
-
     return PSA_SUCCESS;
 
 #else