diff --git a/library/ecdsa.c b/library/ecdsa.c
index dc19384d6..58e1a5fce 100644
--- a/library/ecdsa.c
+++ b/library/ecdsa.c
@@ -172,11 +172,11 @@ static void ecdsa_restart_det_free( mbedtls_ecdsa_restart_det_ctx *ctx )
 }
 #endif /* MBEDTLS_ECDSA_DETERMINISTIC */
 
-#define ECDSA_RS_ECP    &rs_ctx->ecp
+#define ECDSA_RS_ECP    ( rs_ctx == NULL ? NULL : &rs_ctx->ecp )
 
 /* Utility macro for checking and updating ops budget */
 #define ECDSA_BUDGET( ops )   \
-    MBEDTLS_MPI_CHK( mbedtls_ecp_check_budget( grp, &rs_ctx->ecp, ops ) );
+    MBEDTLS_MPI_CHK( mbedtls_ecp_check_budget( grp, ECDSA_RS_ECP, ops ) );
 
 /* Call this when entering a function that needs its own sub-context */
 #define ECDSA_RS_ENTER( SUB )   do {                                 \
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 0b1ebddcf..d106ca6e7 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7777,8 +7777,6 @@ static int ssl_handshake_init( mbedtls_ssl_context *ssl )
             ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_PREPARING;
         else
             ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_WAITING;
-
-        ssl_set_timer( ssl, 0 );
     }
 #endif
 
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 8c53c6700..a77fe1310 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -762,9 +762,27 @@ component_test_full_cmake_clang () {
 component_test_hardcoded_ciphersuite_cmake_clang() {
     msg "build: cmake, full config + MBEDTLS_SSL_CONF_SINGLE_CIPHERSUITE, clang" # ~ 50s
     scripts/config.pl full
-    scripts/config.pl unset MBEDTLS_MEMORY_BACKTRACE # too slow for tests
+    scripts/config.pl unset MBEDTLS_MEMORY_BACKTRACE
+    scripts/config.pl unset MBEDTLS_MEMORY_BUFFER_ALLOC_C
     scripts/config.pl set MBEDTLS_SSL_CONF_SINGLE_CIPHERSUITE MBEDTLS_SUITE_TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8
-    CC=clang cmake -D CMAKE_BUILD_TYPE:String=Check -D ENABLE_TESTING=On .
+    CC=clang cmake -D LINK_WITH_PTHREAD=1 -D CMAKE_BUILD_TYPE:String=ASanDbg -D ENABLE_TESTING=On .
+    make
+
+    msg "test: main suites (full config + MBEDTLS_SSL_CONF_SINGLE_CIPHERSUITE)" # ~ 5s
+    make test
+
+    msg "test: ssl-opt.sh default (full config + MBEDTLS_SSL_CONF_SINGLE_CIPHERSUITE)" # ~ 5s
+    if_build_succeeded tests/ssl-opt.sh -f '^Default$\|^Default, DTLS$'
+}
+
+component_test_hardcoded_timer_callback_cmake_clang() {
+    msg "build: cmake, full config + MBEDTLS_SSL_CONF_SINGLE_CIPHERSUITE, clang" # ~ 50s
+    scripts/config.pl full
+    scripts/config.pl unset MBEDTLS_MEMORY_BACKTRACE
+    scripts/config.pl unset MBEDTLS_MEMORY_BUFFER_ALLOC_C
+    scripts/config.pl set MBEDTLS_SSL_CONF_GET_TIMER mbedtls_timing_get_delay
+    scripts/config.pl set MBEDTLS_SSL_CONF_SET_TIMER mbedtls_timing_set_delay
+    CC=clang cmake -D LINK_WITH_PTHREAD=1 -D CMAKE_BUILD_TYPE:String=ASanDbg -D ENABLE_TESTING=On .
     make
 
     msg "test: main suites (full config + MBEDTLS_SSL_CONF_SINGLE_CIPHERSUITE)" # ~ 5s
diff --git a/tests/suites/test_suite_nist_kw.function b/tests/suites/test_suite_nist_kw.function
index f1acde91a..9c34ea619 100644
--- a/tests/suites/test_suite_nist_kw.function
+++ b/tests/suites/test_suite_nist_kw.function
@@ -170,10 +170,6 @@ void nist_kw_plaintext_lengths( int in_len, int out_len, int mode, int res )
         TEST_ASSERT( ciphertext != NULL );
     }
 
-    memset( plaintext, 0, in_len );
-    memset( ciphertext, 0, output_len );
-
-
     TEST_ASSERT( mbedtls_nist_kw_setkey( &ctx, MBEDTLS_CIPHER_ID_AES,
                                          key, 8 * sizeof( key ), 1 ) == 0 );
 
@@ -225,10 +221,6 @@ void nist_kw_ciphertext_lengths( int in_len, int out_len, int mode, int res )
         TEST_ASSERT( ciphertext != NULL );
     }
 
-    memset( plaintext, 0, output_len );
-    memset( ciphertext, 0, in_len );
-
-
     TEST_ASSERT( mbedtls_nist_kw_setkey( &ctx, MBEDTLS_CIPHER_ID_AES,
                                          key, 8 * sizeof( key ), 0 ) == 0 );
     unwrap_ret = mbedtls_nist_kw_unwrap( &ctx, mode, ciphertext, in_len,