Always check CRYPTO_LOCK_{read,write}_lock

Some functions that lock things are void, so we just return early.

Also make ossl_namemap_empty return 0 on error.  Updated the docs, and added
some code to ossl_namemap_stored() to handle the failure, and updated the
tests to allow for failure.

Fixes: #14230

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14238)

37 files changed, 286 insertions, 139 deletions

diff --git a/crypto/bio/b_addr.c b/crypto/bio/b_addr.c
index 635f84e183..cefa449af0 100644
--- a/crypto/bio/b_addr.c
+++ b/crypto/bio/b_addr.c
@@ -782,7 +782,10 @@ int BIO_lookup_ex(const char *host, const char *service, int lookup_type,
             goto err;
         }
 
-        CRYPTO_THREAD_write_lock(bio_lookup_lock);
+        if (!CRYPTO_THREAD_write_lock(bio_lookup_lock)) {
+            ret = 0;
+            goto err;
+        }
         he_fallback_address = INADDR_ANY;
         if (host == NULL) {
             he = &he_fallback;
diff --git a/crypto/bn/bn_mont.c b/crypto/bn/bn_mont.c
index 934c55850a..b6c4c06bc5 100644
--- a/crypto/bn/bn_mont.c
+++ b/crypto/bn/bn_mont.c
@@ -430,7 +430,8 @@ BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, CRYPTO_RWLOCK *lock,
 {
     BN_MONT_CTX *ret;
 
-    CRYPTO_THREAD_read_lock(lock);
+    if (!CRYPTO_THREAD_read_lock(lock))
+        return NULL;
     ret = *pmont;
     CRYPTO_THREAD_unlock(lock);
     if (ret)
@@ -453,7 +454,11 @@ BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, CRYPTO_RWLOCK *lock,
     }
 
     /* The locked compare-and-set, after the local work is done. */
-    CRYPTO_THREAD_write_lock(lock);
+    if (!CRYPTO_THREAD_write_lock(lock)) {
+        BN_MONT_CTX_free(ret);
+        return NULL;
+    }
+
     if (*pmont) {
         BN_MONT_CTX_free(ret);
         ret = *pmont;
diff --git a/crypto/context.c b/crypto/context.c
index 5a46921778..803111459a 100644
--- a/crypto/context.c
+++ b/crypto/context.c
@@ -232,7 +232,12 @@ static void ossl_lib_ctx_generic_new(void *parent_ign, void *ptr_ign,
     void *ptr = meth->new_func(ctx);
 
     if (ptr != NULL) {
-        CRYPTO_THREAD_write_lock(ctx->lock);
+        if (!CRYPTO_THREAD_write_lock(ctx->lock))
+            /*
+             * Can't return something, so best to hope that something will
+             * fail later. :(
+             */
+            return;
         CRYPTO_set_ex_data(ad, index, ptr);
         CRYPTO_THREAD_unlock(ctx->lock);
     }
@@ -277,21 +282,30 @@ void *ossl_lib_ctx_get_data(OSSL_LIB_CTX *ctx, int index,
     if (ctx == NULL)
         return NULL;
 
-    CRYPTO_THREAD_read_lock(ctx->lock);
+    if (!CRYPTO_THREAD_read_lock(ctx->lock))
+        return NULL;
     dynidx = ctx->dyn_indexes[index];
     CRYPTO_THREAD_unlock(ctx->lock);
 
     if (dynidx != -1) {
-        CRYPTO_THREAD_read_lock(ctx->index_locks[index]);
-        CRYPTO_THREAD_read_lock(ctx->lock);
+        if (!CRYPTO_THREAD_read_lock(ctx->index_locks[index]))
+            return NULL;
+        if (!CRYPTO_THREAD_read_lock(ctx->lock)) {
+            CRYPTO_THREAD_unlock(ctx->index_locks[index]);
+            return NULL;
+        }
         data = CRYPTO_get_ex_data(&ctx->data, dynidx);
         CRYPTO_THREAD_unlock(ctx->lock);
         CRYPTO_THREAD_unlock(ctx->index_locks[index]);
         return data;
     }
 
-    CRYPTO_THREAD_write_lock(ctx->index_locks[index]);
-    CRYPTO_THREAD_write_lock(ctx->lock);
+    if (!CRYPTO_THREAD_write_lock(ctx->index_locks[index]))
+        return NULL;
+    if (!CRYPTO_THREAD_write_lock(ctx->lock)) {
+        CRYPTO_THREAD_unlock(ctx->index_locks[index]);
+        return NULL;
+    }
 
     dynidx = ctx->dyn_indexes[index];
     if (dynidx != -1) {
@@ -321,13 +335,14 @@ void *ossl_lib_ctx_get_data(OSSL_LIB_CTX *ctx, int index,
      */
     if (ossl_crypto_alloc_ex_data_intern(CRYPTO_EX_INDEX_OSSL_LIB_CTX, NULL,
                                          &ctx->data, ctx->dyn_indexes[index])) {
-        CRYPTO_THREAD_read_lock(ctx->lock);
+        if (!CRYPTO_THREAD_read_lock(ctx->lock))
+            goto end;
         data = CRYPTO_get_ex_data(&ctx->data, ctx->dyn_indexes[index]);
         CRYPTO_THREAD_unlock(ctx->lock);
     }
 
+end:
     CRYPTO_THREAD_unlock(ctx->index_locks[index]);
-
     return data;
 }
 
@@ -348,7 +363,8 @@ int ossl_lib_ctx_run_once(OSSL_LIB_CTX *ctx, unsigned int idx,
     if (ctx == NULL)
         return 0;
 
-    CRYPTO_THREAD_read_lock(ctx->oncelock);
+    if (!CRYPTO_THREAD_read_lock(ctx->oncelock))
+        return 0;
     done = ctx->run_once_done[idx];
     if (done)
         ret = ctx->run_once_ret[idx];
@@ -357,7 +373,8 @@ int ossl_lib_ctx_run_once(OSSL_LIB_CTX *ctx, unsigned int idx,
     if (done)
         return ret;
 
-    CRYPTO_THREAD_write_lock(ctx->oncelock);
+    if (!CRYPTO_THREAD_write_lock(ctx->oncelock))
+        return 0;
     if (ctx->run_once_done[idx]) {
         ret = ctx->run_once_ret[idx];
         CRYPTO_THREAD_unlock(ctx->oncelock);
diff --git a/crypto/core_namemap.c b/crypto/core_namemap.c
index b19ca50786..1cc76bf030 100644
--- a/crypto/core_namemap.c
+++ b/crypto/core_namemap.c
@@ -107,7 +107,8 @@ int ossl_namemap_empty(OSSL_NAMEMAP *namemap)
     if (namemap == NULL)
         return 1;
 
-    CRYPTO_THREAD_read_lock(namemap->lock);
+    if (!CRYPTO_THREAD_read_lock(namemap->lock))
+        return -1;
     rv = namemap->max_number == 0;
     CRYPTO_THREAD_unlock(namemap->lock);
     return rv;
@@ -149,9 +150,10 @@ int ossl_namemap_doall_names(const OSSL_NAMEMAP *namemap, int number,
      * the user function, so that we're not holding the read lock when in user
      * code. This could lead to deadlocks.
      */
-    CRYPTO_THREAD_read_lock(namemap->lock);
-    num_names = lh_NAMENUM_ENTRY_num_items(namemap->namenum);
+    if (!CRYPTO_THREAD_read_lock(namemap->lock))
+        return 0;
 
+    num_names = lh_NAMENUM_ENTRY_num_items(namemap->namenum);
     if (num_names == 0) {
         CRYPTO_THREAD_unlock(namemap->lock);
         return 0;
@@ -199,7 +201,8 @@ int ossl_namemap_name2num_n(const OSSL_NAMEMAP *namemap,
     if (namemap == NULL)
         return 0;
 
-    CRYPTO_THREAD_read_lock(namemap->lock);
+    if (!CRYPTO_THREAD_read_lock(namemap->lock))
+        return 0;
     number = namemap_name2num_n(namemap, name, name_len);
     CRYPTO_THREAD_unlock(namemap->lock);
 
@@ -281,7 +284,8 @@ int ossl_namemap_add_name_n(OSSL_NAMEMAP *namemap, int number,
     if (name == NULL || name_len == 0 || namemap == NULL)
         return 0;
 
-    CRYPTO_THREAD_write_lock(namemap->lock);
+    if (!CRYPTO_THREAD_write_lock(namemap->lock))
+        return 0;
     tmp_number = namemap_add_name_n(namemap, number, name, name_len);
     CRYPTO_THREAD_unlock(namemap->lock);
     return tmp_number;
@@ -307,7 +311,8 @@ int ossl_namemap_add_names(OSSL_NAMEMAP *namemap, int number,
         return 0;
     }
 
-    CRYPTO_THREAD_write_lock(namemap->lock);
+    if (!CRYPTO_THREAD_write_lock(namemap->lock))
+        return 0;
     /*
      * Check that no name is an empty string, and that all names have at
      * most one numeric identity together.
@@ -422,12 +427,26 @@ static void get_legacy_md_names(const OBJ_NAME *on, void *arg)
 
 OSSL_NAMEMAP *ossl_namemap_stored(OSSL_LIB_CTX *libctx)
 {
+#ifndef FIPS_MODULE
+    int nms;
+#endif
     OSSL_NAMEMAP *namemap =
         ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_NAMEMAP_INDEX,
                               &stored_namemap_method);
 
+    if (namemap == NULL)
+        return NULL;
+
 #ifndef FIPS_MODULE
-    if (namemap != NULL && ossl_namemap_empty(namemap)) {
+    nms = ossl_namemap_empty(namemap);
+    if (nms < 0) {
+        /*
+         * Could not get lock to make the count, so maybe internal objects
+         * weren't added. This seems safest.
+         */
+        return NULL;
+    }
+    if (nms == 1) {
         /* Before pilfering, we make sure the legacy database is populated */
         OPENSSL_init_crypto(OPENSSL_INIT_ADD_ALL_CIPHERS
                             | OPENSSL_INIT_ADD_ALL_DIGESTS, NULL);
diff --git a/crypto/engine/eng_ctrl.c b/crypto/engine/eng_ctrl.c
index ac770bdeb3..2dc798c1a3 100644
--- a/crypto/engine/eng_ctrl.c
+++ b/crypto/engine/eng_ctrl.c
@@ -132,7 +132,8 @@ int ENGINE_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f) (void))
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
         return 0;
     }
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return 0;
     ref_exists = ((e->struct_ref > 0) ? 1 : 0);
     CRYPTO_THREAD_unlock(global_engine_lock);
     ctrl_exists = ((e->ctrl == NULL) ? 0 : 1);
diff --git a/crypto/engine/eng_dyn.c b/crypto/engine/eng_dyn.c
index 0ce8146f16..2463029c98 100644
--- a/crypto/engine/eng_dyn.c
+++ b/crypto/engine/eng_dyn.c
@@ -157,7 +157,7 @@ static void dynamic_data_ctx_free_func(void *parent, void *ptr,
 static int dynamic_set_data_ctx(ENGINE *e, dynamic_data_ctx **ctx)
 {
     dynamic_data_ctx *c = OPENSSL_zalloc(sizeof(*c));
-    int ret = 1;
+    int ret = 0;
 
     if (c == NULL) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_MALLOC_FAILURE);
@@ -166,13 +166,13 @@ static int dynamic_set_data_ctx(ENGINE *e, dynamic_data_ctx **ctx)
     c->dirs = sk_OPENSSL_STRING_new_null();
     if (c->dirs == NULL) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_MALLOC_FAILURE);
-        OPENSSL_free(c);
-        return 0;
+        goto end;
     }
     c->DYNAMIC_F1 = "v_check";
     c->DYNAMIC_F2 = "bind_engine";
     c->dir_load = 1;
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        goto end;
     if ((*ctx = (dynamic_data_ctx *)ENGINE_get_ex_data(e,
                                                        dynamic_ex_data_idx))
         == NULL) {
@@ -184,11 +184,13 @@ static int dynamic_set_data_ctx(ENGINE *e, dynamic_data_ctx **ctx)
         }
     }
     CRYPTO_THREAD_unlock(global_engine_lock);
+    ret = 1;
     /*
      * If we lost the race to set the context, c is non-NULL and *ctx is the
      * context of the thread that won.
      */
-    if (c)
+end:
+    if (c != NULL)
         sk_OPENSSL_STRING_free(c->dirs);
     OPENSSL_free(c);
     return ret;
@@ -213,7 +215,8 @@ static dynamic_data_ctx *dynamic_get_data_ctx(ENGINE *e)
             ERR_raise(ERR_LIB_ENGINE, ENGINE_R_NO_INDEX);
             return NULL;
         }
-        CRYPTO_THREAD_write_lock(global_engine_lock);
+        if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+            return NULL;
         /* Avoid a race by checking again inside this lock */
         if (dynamic_ex_data_idx < 0) {
             /* Good, someone didn't beat us to it */
diff --git a/crypto/engine/eng_init.c b/crypto/engine/eng_init.c
index 6c9a58fb7a..12a33c5d94 100644
--- a/crypto/engine/eng_init.c
+++ b/crypto/engine/eng_init.c
@@ -63,7 +63,8 @@ int engine_unlocked_finish(ENGINE *e, int unlock_for_handlers)
             CRYPTO_THREAD_unlock(global_engine_lock);
         to_return = e->finish(e);
         if (unlock_for_handlers)
-            CRYPTO_THREAD_write_lock(global_engine_lock);
+            if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+                return 0;
         if (!to_return)
             return 0;
     }
@@ -88,7 +89,8 @@ int ENGINE_init(ENGINE *e)
         ERR_raise(ERR_LIB_ENGINE, ERR_R_MALLOC_FAILURE);
         return 0;
     }
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return 0;
     ret = engine_unlocked_init(e);
     CRYPTO_THREAD_unlock(global_engine_lock);
     return ret;
@@ -101,7 +103,8 @@ int ENGINE_finish(ENGINE *e)
 
     if (e == NULL)
         return 1;
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return 0;
     to_return = engine_unlocked_finish(e, 1);
     CRYPTO_THREAD_unlock(global_engine_lock);
     if (!to_return) {
diff --git a/crypto/engine/eng_list.c b/crypto/engine/eng_list.c
index be08804665..3fa32fa81e 100644
--- a/crypto/engine/eng_list.c
+++ b/crypto/engine/eng_list.c
@@ -138,7 +138,8 @@ ENGINE *ENGINE_get_first(void)
         return NULL;
     }
 
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return NULL;
     ret = engine_list_head;
     if (ret) {
         ret->struct_ref++;
@@ -157,7 +158,8 @@ ENGINE *ENGINE_get_last(void)
         return NULL;
     }
 
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return NULL;
     ret = engine_list_tail;
     if (ret) {
         ret->struct_ref++;
@@ -173,9 +175,10 @@ ENGINE *ENGINE_get_next(ENGINE *e)
     ENGINE *ret = NULL;
     if (e == NULL) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
-        return 0;
+        return NULL;
     }
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return NULL;
     ret = e->next;
     if (ret) {
         /* Return a valid structural reference to the next ENGINE */
@@ -193,9 +196,10 @@ ENGINE *ENGINE_get_prev(ENGINE *e)
     ENGINE *ret = NULL;
     if (e == NULL) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
-        return 0;
+        return NULL;
     }
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return NULL;
     ret = e->prev;
     if (ret) {
         /* Return a valid structural reference to the next ENGINE */
@@ -220,7 +224,8 @@ int ENGINE_add(ENGINE *e)
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_ID_OR_NAME_MISSING);
         return 0;
     }
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return 0;
     if (!engine_list_add(e)) {
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
         to_return = 0;
@@ -237,7 +242,8 @@ int ENGINE_remove(ENGINE *e)
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
         return 0;
     }
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return 0;
     if (!engine_list_remove(e)) {
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_INTERNAL_LIST_ERROR);
         to_return = 0;
@@ -289,7 +295,8 @@ ENGINE *ENGINE_by_id(const char *id)
         return NULL;
     }
 
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return NULL;
     iterator = engine_list_head;
     while (iterator && (strcmp(id, iterator->id) != 0))
         iterator = iterator->next;
diff --git a/crypto/engine/eng_pkey.c b/crypto/engine/eng_pkey.c
index 9feb52d83b..8ba39a46b7 100644
--- a/crypto/engine/eng_pkey.c
+++ b/crypto/engine/eng_pkey.c
@@ -60,23 +60,24 @@ EVP_PKEY *ENGINE_load_private_key(ENGINE *e, const char *key_id,
 
     if (e == NULL) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
-        return 0;
+        return NULL;
     }
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return NULL;
     if (e->funct_ref == 0) {
         CRYPTO_THREAD_unlock(global_engine_lock);
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_NOT_INITIALISED);
-        return 0;
+        return NULL;
     }
     CRYPTO_THREAD_unlock(global_engine_lock);
     if (!e->load_privkey) {
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_NO_LOAD_FUNCTION);
-        return 0;
+        return NULL;
     }
     pkey = e->load_privkey(e, key_id, ui_method, callback_data);
     if (pkey == NULL) {
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_FAILED_LOADING_PRIVATE_KEY);
-        return 0;
+        return NULL;
     }
     return pkey;
 }
@@ -88,23 +89,24 @@ EVP_PKEY *ENGINE_load_public_key(ENGINE *e, const char *key_id,
 
     if (e == NULL) {
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
-        return 0;
+        return NULL;
     }
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return NULL;
     if (e->funct_ref == 0) {
         CRYPTO_THREAD_unlock(global_engine_lock);
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_NOT_INITIALISED);
-        return 0;
+        return NULL;
     }
     CRYPTO_THREAD_unlock(global_engine_lock);
     if (!e->load_pubkey) {
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_NO_LOAD_FUNCTION);
-        return 0;
+        return NULL;
     }
     pkey = e->load_pubkey(e, key_id, ui_method, callback_data);
     if (pkey == NULL) {
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_FAILED_LOADING_PUBLIC_KEY);
-        return 0;
+        return NULL;
     }
     return pkey;
 }
@@ -119,7 +121,8 @@ int ENGINE_load_ssl_client_cert(ENGINE *e, SSL *s,
         ERR_raise(ERR_LIB_ENGINE, ERR_R_PASSED_NULL_PARAMETER);
         return 0;
     }
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return 0;
     if (e->funct_ref == 0) {
         CRYPTO_THREAD_unlock(global_engine_lock);
         ERR_raise(ERR_LIB_ENGINE, ENGINE_R_NOT_INITIALISED);
diff --git a/crypto/engine/eng_table.c b/crypto/engine/eng_table.c
index be5704e93d..aa9b31aeff 100644
--- a/crypto/engine/eng_table.c
+++ b/crypto/engine/eng_table.c
@@ -86,7 +86,9 @@ int engine_table_register(ENGINE_TABLE **table, ENGINE_CLEANUP_CB *cleanup,
 {
     int ret = 0, added = 0;
     ENGINE_PILE tmplate, *fnd;
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return 0;
     if (!(*table))
         added = 1;
     if (!int_table_check(table, 1))
@@ -161,7 +163,9 @@ IMPLEMENT_LHASH_DOALL_ARG(ENGINE_PILE, ENGINE);
 
 void engine_table_unregister(ENGINE_TABLE **table, ENGINE *e)
 {
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        /* Can't return a value. :( */
+        return;
     if (int_table_check(table, 0))
         lh_ENGINE_PILE_doall_ENGINE(&(*table)->piles, int_unregister_cb, e);
     CRYPTO_THREAD_unlock(global_engine_lock);
@@ -179,7 +183,8 @@ static void int_cleanup_cb_doall(ENGINE_PILE *p)
 
 void engine_table_cleanup(ENGINE_TABLE **table)
 {
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return;
     if (*table) {
         lh_ENGINE_PILE_doall(&(*table)->piles, int_cleanup_cb_doall);
         lh_ENGINE_PILE_free(&(*table)->piles);
@@ -206,7 +211,8 @@ ENGINE *engine_table_select_int(ENGINE_TABLE **table, int nid, const char *f,
         return NULL;
     }
     ERR_set_mark();
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        goto end;
     /*
      * Check again inside the lock otherwise we could race against cleanup
      * operations. But don't worry about a debug printout
diff --git a/crypto/engine/tb_asnmth.c b/crypto/engine/tb_asnmth.c
index d1465227b9..fbc0d6f02a 100644
--- a/crypto/engine/tb_asnmth.c
+++ b/crypto/engine/tb_asnmth.c
@@ -199,7 +199,8 @@ const EVP_PKEY_ASN1_METHOD *ENGINE_pkey_asn1_find_str(ENGINE **pe,
         return NULL;
     }
 
-    CRYPTO_THREAD_write_lock(global_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(global_engine_lock))
+        return NULL;
     engine_table_doall(pkey_asn1_meth_table, look_str_cb, &fstr);
     /* If found obtain a structural reference to engine */
     if (fstr.e) {
diff --git a/crypto/err/err.c b/crypto/err/err.c
index a8bde92674..23836b844b 100644
--- a/crypto/err/err.c
+++ b/crypto/err/err.c
@@ -176,7 +176,8 @@ static ERR_STRING_DATA *int_err_get_item(const ERR_STRING_DATA *d)
 {
     ERR_STRING_DATA *p = NULL;
 
-    CRYPTO_THREAD_read_lock(err_string_lock);
+    if (!CRYPTO_THREAD_read_lock(err_string_lock))
+        return NULL;
     p = lh_ERR_STRING_DATA_retrieve(int_error_hash, d);
     CRYPTO_THREAD_unlock(err_string_lock);
 
@@ -238,7 +239,8 @@ static void err_patch(int lib, ERR_STRING_DATA *str)
  */
 static int err_load_strings(const ERR_STRING_DATA *str)
 {
-    CRYPTO_THREAD_write_lock(err_string_lock);
+    if (!CRYPTO_THREAD_write_lock(err_string_lock))
+        return 0;
     for (; str->error; str++)
         (void)lh_ERR_STRING_DATA_insert(int_error_hash,
                                        (ERR_STRING_DATA *)str);
@@ -281,7 +283,8 @@ int ERR_unload_strings(int lib, ERR_STRING_DATA *str)
     if (!RUN_ONCE(&err_string_init, do_err_strings_init))
         return 0;
 
-    CRYPTO_THREAD_write_lock(err_string_lock);
+    if (!CRYPTO_THREAD_write_lock(err_string_lock))
+        return 0;
     /*
      * We don't need to ERR_PACK the lib, since that was done (to
      * the table) when it was loaded.
@@ -728,7 +731,8 @@ int ERR_get_next_error_library(void)
     if (!RUN_ONCE(&err_string_init, do_err_strings_init))
         return 0;
 
-    CRYPTO_THREAD_write_lock(err_string_lock);
+    if (!CRYPTO_THREAD_write_lock(err_string_lock))
+        return 0;
     ret = int_err_library_number++;
     CRYPTO_THREAD_unlock(err_string_lock);
     return ret;
diff --git a/crypto/evp/keymgmt_lib.c b/crypto/evp/keymgmt_lib.c
index 27b9f6b907..4f0dc2d4a7 100644
--- a/crypto/evp/keymgmt_lib.c
+++ b/crypto/evp/keymgmt_lib.c
@@ -101,7 +101,8 @@ void *evp_keymgmt_util_export_to_provider(EVP_PKEY *pk, EVP_KEYMGMT *keymgmt)
     if (pk->keymgmt == keymgmt)
         return pk->keydata;
 
-    CRYPTO_THREAD_read_lock(pk->lock);
+    if (!CRYPTO_THREAD_read_lock(pk->lock))
+        return NULL;
     /*
      * If the provider native "origin" hasn't changed since last time, we
      * try to find our keymgmt in the operation cache.  If it has changed
@@ -156,7 +157,10 @@ void *evp_keymgmt_util_export_to_provider(EVP_PKEY *pk, EVP_KEYMGMT *keymgmt)
         return NULL;
     }
 
-    CRYPTO_THREAD_write_lock(pk->lock);
+    if (!CRYPTO_THREAD_write_lock(pk->lock)) {
+        evp_keymgmt_freedata(keymgmt, import_data.keydata);
+        return NULL;
+    }
     /* Check to make sure some other thread didn't get there first */
     op = evp_keymgmt_util_find_operation_cache(pk, keymgmt);
     if (op != NULL && op->keydata != NULL) {
diff --git a/crypto/ex_data.c b/crypto/ex_data.c
index 291e5a6498..da5b5b69ba 100644
--- a/crypto/ex_data.c
+++ b/crypto/ex_data.c
@@ -43,7 +43,8 @@ static EX_CALLBACKS *get_and_lock(OSSL_EX_DATA_GLOBAL *global, int class_index)
          return NULL;
     }
 
-    CRYPTO_THREAD_write_lock(global->ex_data_lock);
+    if (!CRYPTO_THREAD_write_lock(global->ex_data_lock))
+        return NULL;
     ip = &global->ex_data[class_index];
     return ip;
 }
@@ -367,7 +368,8 @@ void CRYPTO_free_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
         if (storage != NULL)
             f = storage[i];
         else {
-            CRYPTO_THREAD_write_lock(global->ex_data_lock);
+            if (!CRYPTO_THREAD_write_lock(global->ex_data_lock))
+                continue;
             f = sk_EX_CALLBACK_value(ip->meth, i);
             CRYPTO_THREAD_unlock(global->ex_data_lock);
         }
diff --git a/crypto/init.c b/crypto/init.c
index 50aec32c3d..3b6a16a76d 100644
--- a/crypto/init.c
+++ b/crypto/init.c
@@ -586,7 +586,8 @@ int OPENSSL_init_crypto(uint64_t opts, const OPENSSL_INIT_SETTINGS *settings)
         if (settings == NULL) {
             ret = RUN_ONCE(&config, ossl_init_config);
         } else {
-            CRYPTO_THREAD_write_lock(init_lock);
+            if (!CRYPTO_THREAD_write_lock(init_lock))
+                return 0;
             conf_settings = settings;
             ret = RUN_ONCE_ALT(&config, ossl_init_config_settings,
                                ossl_init_config);
diff --git a/crypto/initthread.c b/crypto/initthread.c
index 0697013514..993bf74473 100644
--- a/crypto/initthread.c
+++ b/crypto/initthread.c
@@ -157,7 +157,8 @@ static int init_thread_push_handlers(THREAD_EVENT_HANDLER **hands)
     if (gtr == NULL)
         return 0;
 
-    CRYPTO_THREAD_write_lock(gtr->lock);
+    if (!CRYPTO_THREAD_write_lock(gtr->lock))
+        return 0;
     ret = (sk_THREAD_EVENT_HANDLER_PTR_push(gtr->skhands, hands) != 0);
     CRYPTO_THREAD_unlock(gtr->lock);
 
@@ -172,7 +173,8 @@ static void init_thread_remove_handlers(THREAD_EVENT_HANDLER **handsin)
     gtr = get_global_tevent_register();
     if (gtr == NULL)
         return;
-    CRYPTO_THREAD_write_lock(gtr->lock);
+    if (!CRYPTO_THREAD_write_lock(gtr->lock))
+        return;
     for (i = 0; i < sk_THREAD_EVENT_HANDLER_PTR_num(gtr->skhands); i++) {
         THREAD_EVENT_HANDLER **hands
             = sk_THREAD_EVENT_HANDLER_PTR_value(gtr->skhands, i);
@@ -389,10 +391,12 @@ static int init_thread_deregister(void *index, int all)
     gtr = get_global_tevent_register();
     if (gtr == NULL)
         return 0;
-    if (!all)
-        CRYPTO_THREAD_write_lock(gtr->lock);
-    else
+    if (!all) {
+        if (!CRYPTO_THREAD_write_lock(gtr->lock))
+            return 0;
+    } else {
         glob_tevent_reg = NULL;
+    }
     for (i = 0; i < sk_THREAD_EVENT_HANDLER_PTR_num(gtr->skhands); i++) {
         THREAD_EVENT_HANDLER **hands
             = sk_THREAD_EVENT_HANDLER_PTR_value(gtr->skhands, i);
diff --git a/crypto/mem_sec.c b/crypto/mem_sec.c
index cc4c4e08f6..ebc0e557b5 100644
--- a/crypto/mem_sec.c
+++ b/crypto/mem_sec.c
@@ -132,7 +132,8 @@ void *CRYPTO_secure_malloc(size_t num, const char *file, int line)
     if (!secure_mem_initialized) {
         return CRYPTO_malloc(num, file, line);
     }
-    CRYPTO_THREAD_write_lock(sec_malloc_lock);
+    if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
+        return NULL;
     ret = sh_malloc(num);
     actual_size = ret ? sh_actual_size(ret) : 0;
     secure_mem_used += actual_size;
@@ -164,7 +165,8 @@ void CRYPTO_secure_free(void *ptr, const char *file, int line)
         CRYPTO_free(ptr, file, line);
         return;
     }
-    CRYPTO_THREAD_write_lock(sec_malloc_lock);
+    if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
+        return;
     actual_size = sh_actual_size(ptr);
     CLEAR(ptr, actual_size);
     secure_mem_used -= actual_size;
@@ -188,7 +190,8 @@ void CRYPTO_secure_clear_free(void *ptr, size_t num,
         CRYPTO_free(ptr, file, line);
         return;
     }
-    CRYPTO_THREAD_write_lock(sec_malloc_lock);
+    if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
+        return;
     actual_size = sh_actual_size(ptr);
     CLEAR(ptr, actual_size);
     secure_mem_used -= actual_size;
@@ -209,7 +212,8 @@ int CRYPTO_secure_allocated(const void *ptr)
 
     if (!secure_mem_initialized)
         return 0;
-    CRYPTO_THREAD_write_lock(sec_malloc_lock);
+    if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
+        return 0;
     ret = sh_allocated(ptr);
     CRYPTO_THREAD_unlock(sec_malloc_lock);
     return ret;
@@ -232,7 +236,8 @@ size_t CRYPTO_secure_actual_size(void *ptr)
 #ifndef OPENSSL_NO_SECURE_MEMORY
     size_t actual_size;
 
-    CRYPTO_THREAD_write_lock(sec_malloc_lock);
+    if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
+        return 0;
     actual_size = sh_actual_size(ptr);
     CRYPTO_THREAD_unlock(sec_malloc_lock);
     return actual_size;
diff --git a/crypto/objects/o_names.c b/crypto/objects/o_names.c
index fbc756ebb8..372f65d1ff 100644
--- a/crypto/objects/o_names.c
+++ b/crypto/objects/o_names.c
@@ -86,7 +86,8 @@ int OBJ_NAME_new_index(unsigned long (*hash_func) (const char *),
     if (!OBJ_NAME_init())
         return 0;
 
-    CRYPTO_THREAD_write_lock(obj_lock);
+    if (!CRYPTO_THREAD_write_lock(obj_lock))
+        return 0;
 
     if (name_funcs_stack == NULL)
         name_funcs_stack = sk_NAME_FUNCS_new_null();
@@ -169,7 +170,8 @@ const char *OBJ_NAME_get(const char *name, int type)
         return NULL;
     if (!OBJ_NAME_init())
         return NULL;
-    CRYPTO_THREAD_read_lock(obj_lock);
+    if (!CRYPTO_THREAD_read_lock(obj_lock))
+        return NULL;
 
     alias = type & OBJ_NAME_ALIAS;
     type &= ~OBJ_NAME_ALIAS;
@@ -207,17 +209,18 @@ int OBJ_NAME_add(const char *name, int type, const char *data)
     type &= ~OBJ_NAME_ALIAS;
 
     onp = OPENSSL_malloc(sizeof(*onp));
-    if (onp == NULL) {
-        /* ERROR */
-        goto unlock;
-    }
+    if (onp == NULL)
+        return 0;
 
     onp->name = name;
     onp->alias = alias;
     onp->type = type;
     onp->data = data;
 
-    CRYPTO_THREAD_write_lock(obj_lock);
+    if (!CRYPTO_THREAD_write_lock(obj_lock)) {
+        OPENSSL_free(onp);
+        return 0;
+    }
 
     ret = lh_OBJ_NAME_insert(names_lh, onp);
     if (ret != NULL) {
@@ -256,7 +259,8 @@ int OBJ_NAME_remove(const char *name, int type)
     if (!OBJ_NAME_init())
         return 0;
 
-    CRYPTO_THREAD_write_lock(obj_lock);
+    if (!CRYPTO_THREAD_write_lock(obj_lock))
+        return 0;
 
     type &= ~OBJ_NAME_ALIAS;
     on.name = name;
diff --git a/crypto/provider_core.c b/crypto/provider_core.c
index 47eda52224..f5d54b22ec 100644
--- a/crypto/provider_core.c
+++ b/crypto/provider_core.c
@@ -205,7 +205,8 @@ int ossl_provider_disable_fallback_loading(OSSL_LIB_CTX *libctx)
     struct provider_store_st *store;
 
     if ((store = get_provider_store(libctx)) != NULL) {
-        CRYPTO_THREAD_write_lock(store->lock);
+        if (!CRYPTO_THREAD_write_lock(store->lock))
+            return 0;
         store->use_fallbacks = 0;
         CRYPTO_THREAD_unlock(store->lock);
         return 1;
@@ -233,7 +234,8 @@ OSSL_PROVIDER *ossl_provider_find(OSSL_LIB_CTX *libctx, const char *name,
 #endif
 
         tmpl.name = (char *)name;
-        CRYPTO_THREAD_write_lock(store->lock);
+        if (!CRYPTO_THREAD_write_lock(store->lock))
+            return NULL;
         if ((i = sk_OSSL_PROVIDER_find(store->providers, &tmpl)) == -1
             || (prov = sk_OSSL_PROVIDER_value(store->providers, i)) == NULL
             || !ossl_provider_up_ref(prov))
@@ -303,7 +305,8 @@ OSSL_PROVIDER *ossl_provider_new(OSSL_LIB_CTX *libctx, const char *name,
     if ((prov = provider_new(name, init_function)) == NULL)
         return NULL;
 
-    CRYPTO_THREAD_write_lock(store->lock);
+    if (!CRYPTO_THREAD_write_lock(store->lock))
+        return NULL;
     if (!ossl_provider_up_ref(prov)) { /* +1 One reference for the store */
         ossl_provider_free(prov); /* -1 Reference that was to be returned */
         prov = NULL;
@@ -486,7 +489,8 @@ static int provider_init(OSSL_PROVIDER *prov)
      * modifies a number of things in the provider structure that this
      * function needs to perform under lock anyway.
      */
-    CRYPTO_THREAD_write_lock(prov->flag_lock);
+    if (!CRYPTO_THREAD_write_lock(prov->flag_lock))
+        goto end;
     if (prov->flag_initialized) {
         ok = 1;
         goto end;
@@ -671,7 +675,8 @@ static int provider_deactivate(OSSL_PROVIDER *prov)
         return 0;
 
     if (ref < 1) {
-        CRYPTO_THREAD_write_lock(prov->flag_lock);
+        if (!CRYPTO_THREAD_write_lock(prov->flag_lock))
+            return 0;
         prov->flag_activated = 0;
         CRYPTO_THREAD_unlock(prov->flag_lock);
     }
@@ -688,7 +693,8 @@ static int provider_activate(OSSL_PROVIDER *prov)
         return 0;
 
     if (provider_init(prov)) {
-        CRYPTO_THREAD_write_lock(prov->flag_lock);
+        if (!CRYPTO_THREAD_write_lock(prov->flag_lock))
+            return 0;
         prov->flag_activated = 1;
         CRYPTO_THREAD_unlock(prov->flag_lock);
 
@@ -705,7 +711,10 @@ int ossl_provider_activate(OSSL_PROVIDER *prov, int retain_fallbacks)
         return 0;
     if (provider_activate(prov)) {
         if (!retain_fallbacks) {
-            CRYPTO_THREAD_write_lock(prov->store->lock);
+            if (!CRYPTO_THREAD_write_lock(prov->store->lock)) {
+                provider_deactivate(prov);
+                return 0;
+            }
             prov->store->use_fallbacks = 0;
             CRYPTO_THREAD_unlock(prov->store->lock);
         }
@@ -738,13 +747,15 @@ static void provider_activate_fallbacks(struct provider_store_st *store)
     int activated_fallback_count = 0;
     int i;
 
-    CRYPTO_THREAD_read_lock(store->lock);
+    if (!CRYPTO_THREAD_read_lock(store->lock))
+        return;
     use_fallbacks = store->use_fallbacks;
     CRYPTO_THREAD_unlock(store->lock);
     if (!use_fallbacks)
         return;
 
-    CRYPTO_THREAD_write_lock(store->lock);
+    if (!CRYPTO_THREAD_write_lock(store->lock))
+        return;
     /* Check again, just in case another thread changed it */
     use_fallbacks = store->use_fallbacks;
     if (!use_fallbacks) {
@@ -804,7 +815,8 @@ int ossl_provider_doall_activated(OSSL_LIB_CTX *ctx,
      * Under lock, grab a copy of the provider list and up_ref each
      * provider so that they don't disappear underneath us.
      */
-    CRYPTO_THREAD_read_lock(store->lock);
+    if (!CRYPTO_THREAD_read_lock(store->lock))
+        return 0;
     provs = sk_OSSL_PROVIDER_dup(store->providers);
     if (provs == NULL) {
         CRYPTO_THREAD_unlock(store->lock);
@@ -973,7 +985,8 @@ int ossl_provider_set_operation_bit(OSSL_PROVIDER *provider, size_t bitnum)
     size_t byte = bitnum / 8;
     unsigned char bit = (1 << (bitnum % 8)) & 0xFF;
 
-    CRYPTO_THREAD_write_lock(provider->opbits_lock);
+    if (!CRYPTO_THREAD_write_lock(provider->opbits_lock))
+        return 0;
     if (provider->operation_bits_sz <= byte) {
         unsigned char *tmp = OPENSSL_realloc(provider->operation_bits,
                                              byte + 1);
@@ -1005,7 +1018,8 @@ int ossl_provider_test_operation_bit(OSSL_PROVIDER *provider, size_t bitnum,
     }
 
     *result = 0;
-    CRYPTO_THREAD_read_lock(provider->opbits_lock);
+    if (!CRYPTO_THREAD_read_lock(provider->opbits_lock))
+        return 0;
     if (provider->operation_bits_sz > byte)
         *result = ((provider->operation_bits[byte] & bit) != 0);
     CRYPTO_THREAD_unlock(provider->opbits_lock);
diff --git a/crypto/rand/rand_lib.c b/crypto/rand/rand_lib.c
index e248d5753a..3cd34198c1 100644
--- a/crypto/rand/rand_lib.c
+++ b/crypto/rand/rand_lib.c
@@ -163,7 +163,8 @@ int RAND_set_rand_method(const RAND_METHOD *meth)
     if (!RUN_ONCE(&rand_init, do_rand_init))
         return 0;
 
-    CRYPTO_THREAD_write_lock(rand_meth_lock);
+    if (!CRYPTO_THREAD_write_lock(rand_meth_lock))
+        return 0;
 #  ifndef OPENSSL_NO_ENGINE
     ENGINE_finish(funct_ref);
     funct_ref = NULL;
@@ -180,7 +181,8 @@ const RAND_METHOD *RAND_get_rand_method(void)
     if (!RUN_ONCE(&rand_init, do_rand_init))
         return NULL;
 
-    CRYPTO_THREAD_write_lock(rand_meth_lock);
+    if (!CRYPTO_THREAD_write_lock(rand_meth_lock))
+        return NULL;
     if (default_RAND_meth == NULL) {
 #  ifndef OPENSSL_NO_ENGINE
         ENGINE *e;
@@ -220,7 +222,11 @@ int RAND_set_rand_engine(ENGINE *engine)
             return 0;
         }
     }
-    CRYPTO_THREAD_write_lock(rand_engine_lock);
+    if (!CRYPTO_THREAD_write_lock(rand_engine_lock)) {
+        ENGINE_finish(engine);
+        return 0;
+    }
+
     /* This function releases any prior ENGINE so call it first */
     RAND_set_rand_method(tmp_meth);
     funct_ref = engine;
diff --git a/crypto/rsa/rsa_ossl.c b/crypto/rsa/rsa_ossl.c
index b92137ee0a..9f98c037c8 100644
--- a/crypto/rsa/rsa_ossl.c
+++ b/crypto/rsa/rsa_ossl.c
@@ -163,7 +163,8 @@ static BN_BLINDING *rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx)
 {
     BN_BLINDING *ret;
 
-    CRYPTO_THREAD_write_lock(rsa->lock);
+    if (!CRYPTO_THREAD_write_lock(rsa->lock))
+        return NULL;
 
     if (rsa->blinding == NULL) {
         rsa->blinding = RSA_setup_blinding(rsa, ctx);
diff --git a/crypto/store/store_register.c b/crypto/store/store_register.c
index 51bd591790..5049671f52 100644
--- a/crypto/store/store_register.c
+++ b/crypto/store/store_register.c
@@ -194,7 +194,8 @@ int ossl_store_register_loader_int(OSSL_STORE_LOADER *loader)
         ERR_raise(ERR_LIB_OSSL_STORE, ERR_R_MALLOC_FAILURE);
         return 0;
     }
-    CRYPTO_THREAD_write_lock(registry_lock);
+    if (!CRYPTO_THREAD_write_lock(registry_lock))
+        return 0;
 
     if (ossl_store_register_init()
         && (lh_OSSL_STORE_LOADER_insert(loader_register, loader) != NULL
@@ -226,7 +227,8 @@ const OSSL_STORE_LOADER *ossl_store_get0_loader_int(const char *scheme)
         ERR_raise(ERR_LIB_OSSL_STORE, ERR_R_MALLOC_FAILURE);
         return NULL;
     }
-    CRYPTO_THREAD_write_lock(registry_lock);
+    if (!CRYPTO_THREAD_write_lock(registry_lock))
+        return NULL;
 
     if (!ossl_store_register_init())
         ERR_raise(ERR_LIB_OSSL_STORE, ERR_R_INTERNAL_ERROR);
@@ -255,7 +257,8 @@ OSSL_STORE_LOADER *ossl_store_unregister_loader_int(const char *scheme)
         ERR_raise(ERR_LIB_OSSL_STORE, ERR_R_MALLOC_FAILURE);
         return NULL;
     }
-    CRYPTO_THREAD_write_lock(registry_lock);
+    if (!CRYPTO_THREAD_write_lock(registry_lock))
+        return NULL;
 
     if (!ossl_store_register_init())
         ERR_raise(ERR_LIB_OSSL_STORE, ERR_R_INTERNAL_ERROR);
diff --git a/crypto/threads_none.c b/crypto/threads_none.c
index 55d4b5f0f8..f0e0f7fba4 100644
--- a/crypto/threads_none.c
+++ b/crypto/threads_none.c
@@ -31,14 +31,14 @@ CRYPTO_RWLOCK *CRYPTO_THREAD_lock_new(void)
     return lock;
 }
 
-int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock)
+__owur int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock)
 {
     if (!ossl_assert(*(unsigned int *)lock == 1))
         return 0;
     return 1;
 }
 
-int CRYPTO_THREAD_write_lock(CRYPTO_RWLOCK *lock)
+__owur int CRYPTO_THREAD_write_lock(CRYPTO_RWLOCK *lock)
 {
     if (!ossl_assert(*(unsigned int *)lock == 1))
         return 0;
diff --git a/crypto/threads_pthread.c b/crypto/threads_pthread.c
index e81f3cf1ef..ecb53299c4 100644
--- a/crypto/threads_pthread.c
+++ b/crypto/threads_pthread.c
@@ -73,7 +73,7 @@ CRYPTO_RWLOCK *CRYPTO_THREAD_lock_new(void)
     return lock;
 }
 
-int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock)
+__owur int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock)
 {
 # ifdef USE_RWLOCK
     if (pthread_rwlock_rdlock(lock) != 0)
@@ -88,7 +88,7 @@ int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock)
     return 1;
 }
 
-int CRYPTO_THREAD_write_lock(CRYPTO_RWLOCK *lock)
+__owur int CRYPTO_THREAD_write_lock(CRYPTO_RWLOCK *lock)
 {
 # ifdef USE_RWLOCK
     if (pthread_rwlock_wrlock(lock) != 0)
diff --git a/crypto/threads_win.c b/crypto/threads_win.c
index 085ce9e96c..fdc32a2a54 100644
--- a/crypto/threads_win.c
+++ b/crypto/threads_win.c
@@ -57,7 +57,7 @@ CRYPTO_RWLOCK *CRYPTO_THREAD_lock_new(void)
     return lock;
 }
 
-int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock)
+__owur int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock)
 {
 # ifdef USE_RWLOCK
     CRYPTO_win_rwlock *rwlock = lock;
@@ -69,7 +69,7 @@ int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock)
     return 1;
 }
 
-int CRYPTO_THREAD_write_lock(CRYPTO_RWLOCK *lock)
+__owur int CRYPTO_THREAD_write_lock(CRYPTO_RWLOCK *lock)
 {
 # ifdef USE_RWLOCK
     CRYPTO_win_rwlock *rwlock = lock;
diff --git a/crypto/trace.c b/crypto/trace.c
index ba9b8dd742..12fe02acfc 100644
--- a/crypto/trace.c
+++ b/crypto/trace.c
@@ -468,7 +468,8 @@ BIO *OSSL_trace_begin(int category)
     prefix = trace_channels[category].prefix;
 
     if (channel != NULL) {
-        CRYPTO_THREAD_write_lock(trace_lock);
+        if (!CRYPTO_THREAD_write_lock(trace_lock))
+            return NULL;
         current_channel = channel;
         switch (trace_channels[category].type) {
         case SIMPLE_CHANNEL:
diff --git a/crypto/ui/ui_openssl.c b/crypto/ui/ui_openssl.c
index 0a38658c72..42524d42a2 100644
--- a/crypto/ui/ui_openssl.c
+++ b/crypto/ui/ui_openssl.c
@@ -372,7 +372,8 @@ static int read_string_inner(UI *ui, UI_STRING *uis, int echo, int strip_nl)
 /* Internal functions to open, handle and close a channel to the console.  */
 static int open_console(UI *ui)
 {
-    CRYPTO_THREAD_write_lock(ui->lock);
+    if (!CRYPTO_THREAD_write_lock(ui->lock))
+        return 0;
     is_a_tty = 1;
 
 # if defined(OPENSSL_SYS_VXWORKS)
diff --git a/crypto/x509/by_dir.c b/crypto/x509/by_dir.c
index 1e5e8469aa..6c0894796b 100644
--- a/crypto/x509/by_dir.c
+++ b/crypto/x509/by_dir.c
@@ -268,7 +268,8 @@ static int get_cert_by_subject_ex(X509_LOOKUP *xl, X509_LOOKUP_TYPE type,
         }
         if (type == X509_LU_CRL && ent->hashes) {
             htmp.hash = h;
-            CRYPTO_THREAD_read_lock(ctx->lock);
+            if (!CRYPTO_THREAD_read_lock(ctx->lock))
+                goto finish;
             idx = sk_BY_DIR_HASH_find(ent->hashes, &htmp);
             if (idx >= 0) {
                 hent = sk_BY_DIR_HASH_value(ent->hashes, idx);
@@ -346,7 +347,8 @@ static int get_cert_by_subject_ex(X509_LOOKUP *xl, X509_LOOKUP_TYPE type,
         /* If a CRL, update the last file suffix added for this */
 
         if (type == X509_LU_CRL) {
-            CRYPTO_THREAD_write_lock(ctx->lock);
+            if (!CRYPTO_THREAD_write_lock(ctx->lock))
+                goto finish;
             /*
              * Look for entry again in case another thread added an entry
              * first.
diff --git a/crypto/x509/pcy_cache.c b/crypto/x509/pcy_cache.c
index cc7aaba1e9..22cf431895 100644
--- a/crypto/x509/pcy_cache.c
+++ b/crypto/x509/pcy_cache.c
@@ -188,7 +188,8 @@ const X509_POLICY_CACHE *policy_cache_set(X509 *x)
 {
 
     if (x->policy_cache == NULL) {
-        CRYPTO_THREAD_write_lock(x->lock);
+        if (!CRYPTO_THREAD_write_lock(x->lock))
+            return NULL;
         policy_cache_new(x);
         CRYPTO_THREAD_unlock(x->lock);
     }
diff --git a/crypto/x509/v3_purp.c b/crypto/x509/v3_purp.c
index 1149e83780..ee2d3c7289 100644
--- a/crypto/x509/v3_purp.c
+++ b/crypto/x509/v3_purp.c
@@ -411,7 +411,8 @@ int x509v3_cache_extensions(X509 *x)
         return (x->ex_flags & EXFLAG_INVALID) == 0;
 #endif
 
-    CRYPTO_THREAD_write_lock(x->lock);
+    if (!CRYPTO_THREAD_write_lock(x->lock))
+        return 0;
     if (x->ex_flags & EXFLAG_SET) { /* Cert has already been processed */
         CRYPTO_THREAD_unlock(x->lock);
         return (x->ex_flags & EXFLAG_INVALID) == 0;
diff --git a/crypto/x509/x_crl.c b/crypto/x509/x_crl.c
index 4058202b77..4bb7a880a3 100644
--- a/crypto/x509/x_crl.c
+++ b/crypto/x509/x_crl.c
@@ -427,7 +427,8 @@ static int def_crl_lookup(X509_CRL *crl,
      * under a lock to avoid race condition.
      */
     if (!sk_X509_REVOKED_is_sorted(crl->crl.revoked)) {
-        CRYPTO_THREAD_write_lock(crl->lock);
+        if (!CRYPTO_THREAD_write_lock(crl->lock))
+            return 0;
         sk_X509_REVOKED_sort(crl->crl.revoked);
         CRYPTO_THREAD_unlock(crl->lock);
     }
diff --git a/doc/internal/man3/ossl_namemap_new.pod b/doc/internal/man3/ossl_namemap_new.pod
index d6f30a7047..ff247e87b0 100644
--- a/doc/internal/man3/ossl_namemap_new.pod
+++ b/doc/internal/man3/ossl_namemap_new.pod
@@ -85,7 +85,8 @@ ossl_namemap_new() and ossl_namemap_stored() return the pointer to a
 B<OSSL_NAMEMAP>, or NULL on error.
 
 ossl_namemap_empty() returns 1 if the B<OSSL_NAMEMAP> is NULL or
-empty, or 0 if it's not empty.
+empty, 0 if it's not empty, or -1 on internal error (such as inability
+to lock).
 
 ossl_namemap_add_name() and ossl_namemap_add_name_n() return the number
 associated with the added string, or zero on error.
diff --git a/include/openssl/crypto.h.in b/include/openssl/crypto.h.in
index d7c4dd7426..adceb0c103 100644
--- a/include/openssl/crypto.h.in
+++ b/include/openssl/crypto.h.in
@@ -79,8 +79,8 @@ typedef struct {
 typedef void CRYPTO_RWLOCK;
 
 CRYPTO_RWLOCK *CRYPTO_THREAD_lock_new(void);
-int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock);
-int CRYPTO_THREAD_write_lock(CRYPTO_RWLOCK *lock);
+__owur int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock);
+__owur int CRYPTO_THREAD_write_lock(CRYPTO_RWLOCK *lock);
 int CRYPTO_THREAD_unlock(CRYPTO_RWLOCK *lock);
 void CRYPTO_THREAD_lock_free(CRYPTO_RWLOCK *lock);
 
diff --git a/providers/fips/self_test.c b/providers/fips/self_test.c
index b20af1bd6c..dbd744ff7c 100644
--- a/providers/fips/self_test.c
+++ b/providers/fips/self_test.c
@@ -11,6 +11,7 @@
 #include <openssl/evp.h>
 #include <openssl/params.h>
 #include <openssl/crypto.h>
+#include <internal/cryptlib.h>
 #include <openssl/fipskey.h>
 #include <openssl/err.h>
 #include <openssl/proverr.h>
@@ -212,9 +213,10 @@ err:
 
 static void set_fips_state(int state)
 {
-    CRYPTO_THREAD_write_lock(fips_state_lock);
-    FIPS_state = state;
-    CRYPTO_THREAD_unlock(fips_state_lock);
+    if (ossl_assert(CRYPTO_THREAD_write_lock(fips_state_lock) != 0)) {
+        FIPS_state = state;
+        CRYPTO_THREAD_unlock(fips_state_lock);
+    }
 }
 
 /* This API is triggered either on loading of the FIPS module or on demand */
@@ -232,7 +234,8 @@ int SELF_TEST_post(SELF_TEST_POST_PARAMS *st, int on_demand_test)
     if (!RUN_ONCE(&fips_self_test_init, do_fips_self_test_init))
         return 0;
 
-    CRYPTO_THREAD_read_lock(fips_state_lock);
+    if (!CRYPTO_THREAD_read_lock(fips_state_lock))
+        return 0;
     loclstate = FIPS_state;
     CRYPTO_THREAD_unlock(fips_state_lock);
 
@@ -244,8 +247,12 @@ int SELF_TEST_post(SELF_TEST_POST_PARAMS *st, int on_demand_test)
         return 0;
     }
 
-    CRYPTO_THREAD_write_lock(self_test_lock);
-    CRYPTO_THREAD_read_lock(fips_state_lock);
+    if (!CRYPTO_THREAD_write_lock(self_test_lock))
+        return 0;
+    if (!CRYPTO_THREAD_read_lock(fips_state_lock)) {
+        CRYPTO_THREAD_unlock(self_test_lock);
+        return 0;
+    }
     if (FIPS_state == FIPS_STATE_RUNNING) {
         CRYPTO_THREAD_unlock(fips_state_lock);
         if (!on_demand_test) {
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 348b507622..4cb40bd89b 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -893,7 +893,8 @@ int SSL_set_session_id_context(SSL *ssl, const unsigned char *sid_ctx,
 
 int SSL_CTX_set_generate_session_id(SSL_CTX *ctx, GEN_SESSION_CB cb)
 {
-    CRYPTO_THREAD_write_lock(ctx->lock);
+    if (!CRYPTO_THREAD_write_lock(ctx->lock))
+        return 0;
     ctx->generate_session_id = cb;
     CRYPTO_THREAD_unlock(ctx->lock);
     return 1;
@@ -901,7 +902,8 @@ int SSL_CTX_set_generate_session_id(SSL_CTX *ctx, GEN_SESSION_CB cb)
 
 int SSL_set_generate_session_id(SSL *ssl, GEN_SESSION_CB cb)
 {
-    CRYPTO_THREAD_write_lock(ssl->lock);
+    if (!CRYPTO_THREAD_write_lock(ssl->lock))
+        return 0;
     ssl->generate_session_id = cb;
     CRYPTO_THREAD_unlock(ssl->lock);
     return 1;
@@ -926,7 +928,8 @@ int SSL_has_matching_session_id(const SSL *ssl, const unsigned char *id,
     r.session_id_length = id_len;
     memcpy(r.session_id, id, id_len);
 
-    CRYPTO_THREAD_read_lock(ssl->session_ctx->lock);
+    if (!CRYPTO_THREAD_read_lock(ssl->session_ctx->lock))
+        return 0;
     p = lh_SSL_SESSION_retrieve(ssl->session_ctx->sessions, &r);
     CRYPTO_THREAD_unlock(ssl->session_ctx->lock);
     return (p != NULL);
diff --git a/ssl/ssl_sess.c b/ssl/ssl_sess.c
index 2bb7609395..4e4f9aacea 100644
--- a/ssl/ssl_sess.c
+++ b/ssl/ssl_sess.c
@@ -44,7 +44,8 @@ SSL_SESSION *SSL_get1_session(SSL *ssl)
      * somebody doesn't free ssl->session between when we check it's non-null
      * and when we up the reference count.
      */
-    CRYPTO_THREAD_read_lock(ssl->lock);
+    if (!CRYPTO_THREAD_read_lock(ssl->lock))
+        return NULL;
     sess = ssl->session;
     if (sess)
         SSL_SESSION_up_ref(sess);
@@ -319,8 +320,14 @@ int ssl_generate_session_id(SSL *s, SSL_SESSION *ss)
     }
 
     /* Choose which callback will set the session ID */
-    CRYPTO_THREAD_read_lock(s->lock);
-    CRYPTO_THREAD_read_lock(s->session_ctx->lock);
+    if (!CRYPTO_THREAD_read_lock(s->lock))
+        return 0;
+    if (!CRYPTO_THREAD_read_lock(s->session_ctx->lock)) {
+        CRYPTO_THREAD_unlock(s->lock);
+        SSLfatal(s, SSL_AD_INTERNAL_ERROR,
+                 SSL_R_SESSION_ID_CONTEXT_UNINITIALIZED);
+        return 0;
+    }
     if (s->generate_session_id)
         cb = s->generate_session_id;
     else if (s->session_ctx->generate_session_id)
@@ -428,7 +435,8 @@ SSL_SESSION *lookup_sess_in_cache(SSL *s, const unsigned char *sess_id,
         memcpy(data.session_id, sess_id, sess_id_len);
         data.session_id_length = sess_id_len;
 
-        CRYPTO_THREAD_read_lock(s->session_ctx->lock);
+        if (!CRYPTO_THREAD_read_lock(s->session_ctx->lock))
+            return NULL;
         ret = lh_SSL_SESSION_retrieve(s->session_ctx->sessions, &data);
         if (ret != NULL) {
             /* don't allow other threads to steal it: */
@@ -643,7 +651,10 @@ int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *c)
      * if session c is in already in cache, we take back the increment later
      */
 
-    CRYPTO_THREAD_write_lock(ctx->lock);
+    if (!CRYPTO_THREAD_write_lock(ctx->lock)) {
+        SSL_SESSION_free(c);
+        return 0;
+    }
     s = lh_SSL_SESSION_insert(ctx->sessions, c);
 
     /*
@@ -716,8 +727,10 @@ static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck)
     int ret = 0;
 
     if ((c != NULL) && (c->session_id_length != 0)) {
-        if (lck)
-            CRYPTO_THREAD_write_lock(ctx->lock);
+        if (lck) {
+            if (!CRYPTO_THREAD_write_lock(ctx->lock))
+                return 0;
+        }
         if ((r = lh_SSL_SESSION_retrieve(ctx->sessions, c)) != NULL) {
             ret = 1;
             r = lh_SSL_SESSION_delete(ctx->sessions, r);
@@ -733,8 +746,7 @@ static int remove_session_lock(SSL_CTX *ctx, SSL_SESSION *c, int lck)
 
         if (ret)
             SSL_SESSION_free(r);
-    } else
-        ret = 0;
+    }
     return ret;
 }
 
@@ -1068,7 +1080,8 @@ void SSL_CTX_flush_sessions(SSL_CTX *s, long t)
     if (tp.cache == NULL)
         return;
     tp.time = t;
-    CRYPTO_THREAD_write_lock(s->lock);
+    if (!CRYPTO_THREAD_write_lock(s->lock))
+        return;
     i = lh_SSL_SESSION_get_down_load(s->sessions);
     lh_SSL_SESSION_set_down_load(s->sessions, 0);
     lh_SSL_SESSION_doall_TIMEOUT_PARAM(tp.cache, timeout_cb, &tp);
diff --git a/test/namemap_internal_test.c b/test/namemap_internal_test.c
index c1f77561e4..6c6095a40a 100644
--- a/test/namemap_internal_test.c
+++ b/test/namemap_internal_test.c
@@ -21,11 +21,11 @@ static int test_namemap_empty(void)
     OSSL_NAMEMAP *nm = NULL;
     int ok;
 
-    ok = TEST_true(ossl_namemap_empty(NULL))
+    ok = TEST_int_eq(ossl_namemap_empty(NULL), 1)
          && TEST_ptr(nm = ossl_namemap_new())
-         && TEST_true(ossl_namemap_empty(nm))
+         && TEST_int_eq(ossl_namemap_empty(nm), 1)
          && TEST_int_ne(ossl_namemap_add_name(nm, 0, NAME1), 0)
-         && TEST_false(ossl_namemap_empty(nm));
+         && TEST_int_eq(ossl_namemap_empty(nm), 0);
     ossl_namemap_free(nm);
     return ok;
 }