[macOS] fix potential leaks in error paths (#2707)

...affecting Process memory_full_info() and threads()

Author: giampaolo

HISTORY.rst

@@ -18,6 +18,8 @@ XXXX-XX
 
 - 2701_, [macOS]: fix compilation error on macOS < 10.7.  (patch by Sergey
   Fedorov)
+- 2707_, [macOS]: fix potential memory leaks in error paths of
+  `Process.memory_full_info()` and `Process.threads()`.
 
 7.2.1
 =====

psutil/arch/osx/proc.c

@@ -291,6 +291,7 @@ psutil_proc_memory_uss(PyObject *self, PyObject *args) {
     if (psutil_sysctlbyname("sysctl.proc_cputype", &cpu_type, sizeof(cpu_type))
         != 0)
     {
+        mach_port_deallocate(mach_task_self(), task);
         return NULL;
     }
 
@@ -299,6 +300,7 @@ psutil_proc_memory_uss(PyObject *self, PyObject *args) {
     for (addr = MACH_VM_MIN_ADDRESS;; addr += size) {
         prev_addr = addr;
         info_count = VM_REGION_TOP_INFO_COUNT;  // reset before each call
+        object_name = MACH_PORT_NULL;
 
         kr = mach_vm_region(
             task,
@@ -309,6 +311,12 @@ psutil_proc_memory_uss(PyObject *self, PyObject *args) {
             &info_count,
             &object_name
         );
+
+        if (object_name != MACH_PORT_NULL) {
+            mach_port_deallocate(mach_task_self(), object_name);
+            object_name = MACH_PORT_NULL;
+        }
+
         if (kr == KERN_INVALID_ADDRESS) {
             // Done iterating VM regions.
             break;
@@ -439,15 +447,20 @@ psutil_proc_threads(PyObject *self, PyObject *args) {
         Py_CLEAR(py_tuple);
     }
 
+    // deallocate thread_list if it was allocated
     if (thread_list != NULL) {
         vm_deallocate(
             mach_task_self(),
             (vm_address_t)thread_list,
             thread_count * sizeof(thread_act_t)
         );
+        thread_list = NULL;
     }
+
+    // deallocate the task port
     if (task != MACH_PORT_NULL) {
         mach_port_deallocate(mach_task_self(), task);
+        task = MACH_PORT_NULL;
     }
 
     return py_retlist;
@@ -462,9 +475,12 @@ psutil_proc_threads(PyObject *self, PyObject *args) {
             (vm_address_t)thread_list,
             thread_count * sizeof(thread_act_t)
         );
+        thread_list = NULL;
     }
+
     if (task != MACH_PORT_NULL) {
         mach_port_deallocate(mach_task_self(), task);
+        task = MACH_PORT_NULL;
     }
 
     return NULL;