Make sure TRACKER is not used after being destroyed

Make sure TRACKER is not used after being destroyed.
Also add checks to umfMemoryTrackerGetPool()
to detect if TRACKER or its map is not initialized.

Signed-off-by: Lukasz Dorau <[email protected]>

Author: ldorau

src/libumf_linux.c

@@ -19,7 +19,10 @@ void __attribute__((constructor)) umfCreate(void) {
 }
 
 void __attribute__((destructor)) umfDestroy(void) {
-    umfMemoryTrackerDestroy(TRACKER);
+    umf_memory_tracker_handle_t t = TRACKER;
+    // make sure TRACKER is not used after being destroyed
+    TRACKER = NULL;
+    umfMemoryTrackerDestroy(t);
 }
 
 void libumfInit(void) {

src/provider/provider_tracking.c

@@ -81,6 +81,16 @@ static umf_result_t umfMemoryTrackerRemove(umf_memory_tracker_handle_t hTracker,
 umf_memory_pool_handle_t umfMemoryTrackerGetPool(const void *ptr) {
     assert(ptr);
 
+    if (TRACKER == NULL) {
+        fprintf(stderr, "tracker is not created\n");
+        return NULL;
+    }
+
+    if (TRACKER->map == NULL) {
+        fprintf(stderr, "tracker's map is not created\n");
+        return NULL;
+    }
+
     uintptr_t rkey;
     tracker_value_t *rvalue;
     int found = critnib_find(TRACKER->map, (uintptr_t)ptr, FIND_LE,