diff --git a/framework/allocator.cpp b/framework/allocator.cpp
index 371a288..f7b6c9f 100644
--- a/framework/allocator.cpp
+++ b/framework/allocator.cpp
@@ -14,23 +14,29 @@
 
 void heap_free(pst_allocator* alloc, void* buff)
 {
+    pthread_mutex_lock(&alloc->lock);
     alloc->size -= malloc_usable_size(buff);
+    pthread_mutex_unlock(&alloc->lock);
     free(buff);
 }
 
 void* heap_alloc(pst_allocator* alloc, uint32_t size)
 {
     void* buff = malloc(size);
+    pthread_mutex_lock(&alloc->lock);
     alloc->size += malloc_usable_size(buff);
+    pthread_mutex_unlock(&alloc->lock);
 
     return buff;
 }
 
 void* heap_realloc(pst_allocator* alloc, void* buff, uint32_t new_size)
 {
+    pthread_mutex_lock(&alloc->lock);
     alloc->size -= malloc_usable_size(buff);
     void* new_buff = realloc(buff, new_size);
     alloc->size += malloc_usable_size(new_buff);
+    pthread_mutex_unlock(&alloc->lock);
 
     return new_buff;
 }
@@ -45,6 +51,8 @@ void pst_alloc_init(pst_allocator* alloc)
     alloc->free = heap_free;
     alloc->realloc = heap_realloc;
 
+    pthread_mutex_init(&alloc->lock, NULL);
+
     return;
 }
 
@@ -62,4 +70,6 @@ void pst_alloc_fini(pst_allocator* alloc)
         alloc->base = NULL;
         alloc->size = 0;
     }
+
+    pthread_mutex_destroy(&alloc->lock);
 }
diff --git a/framework/allocator.h b/framework/allocator.h
index 9896124..75a0a6e 100644
--- a/framework/allocator.h
+++ b/framework/allocator.h
@@ -10,6 +10,7 @@
 
 #include <stdint.h>
 #include <assert.h>
+#include <pthread.h>
 
 // concatenation
 #define CAT(a, ...) CAT2(a, __VA_ARGS__)
@@ -27,26 +28,24 @@
 #define pst_fini(TYPE, NAME) \
     CAT2(TYPE, _fini) (NAME);
 
-typedef struct __pst_allocator pst_allocator;
-
-typedef void* (*pst_alloc_def)(pst_allocator* alloc, uint32_t size);
-typedef void (*pst_free_def)(pst_allocator* alloc, void* buff);
-typedef void* (*pst_realloc_def)(pst_allocator* alloc, void* buff, uint32_t new_size);
-
 typedef enum {
     ALLOC_NONE = 0,     // not initialized
     ALLOC_HEAP = 1,     // use libc memory allocator
     ALLOC_CUSTOM = 2    // use custom allocator in predefined range of memory
 } pst_alloc_type;
 
-typedef struct __pst_allocator {
+typedef struct pst_allocator {
+    // methods
+    void* (*alloc)(pst_allocator* alloc, uint32_t size);
+    void (*free)(pst_allocator* alloc, void* buff);
+    void* (*realloc)(pst_allocator* alloc, void* buff, uint32_t new_size);
+
+    // fields
     int             type;
     void*           base;
     uint32_t        size;
-    // routines
-    pst_alloc_def   alloc;
-    pst_free_def    free;
-    pst_realloc_def realloc;
+    pthread_mutex_t lock;
+
 } pst_allocator;
 
 void pst_alloc_init(pst_allocator* alloc);