Merge pull request #2548 from REW1L/fix-issue-2543

Fix issue #2543 segfault in font dealloc after reinit
pygame · Oct 23, 2021 · b72ba79 · b72ba79
2 parents c19a66e + d495000
commit b72ba79
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Showing 3 changed files with 23 additions and 2 deletions.
diff --git a/src_c/font.c b/src_c/font.c
@@ -65,6 +65,7 @@ PyFont_New(TTF_Font *);
 #define PyFont_Check(x) ((x)->ob_type == &PyFont_Type)
 
 static int font_initialized = 0;
+static unsigned int current_ttf_generation = 0;
 static const char font_defaultname[] = "freesansbold.ttf";
 static const char pkgdatamodule_name[] = "pygame.pkgdata";
 static const char resourcefunc_name[] = "getResource";
@@ -200,6 +201,7 @@ fontmodule_quit(PyObject *self)
     if (font_initialized) {
         TTF_Quit();
         font_initialized = 0;
+        current_ttf_generation++;
     }
     Py_RETURN_NONE;
 }
@@ -730,9 +732,16 @@ static void
 font_dealloc(PyFontObject *self)
 {
     TTF_Font *font = PyFont_AsFont(self);
-
-    if (font && font_initialized)
+    if (font && font_initialized) {
+        if (self->ttf_init_generation != current_ttf_generation) {
+            // Since TTF_Font is a private structure
+            // it's impossible to access face field in a common way.
+            int** face_pp = font;
+            *face_pp = NULL;
+        }
         TTF_CloseFont(font);
+        self->font = NULL;
+    }
 
     if (self->weakreflist)
         PyObject_ClearWeakRefs((PyObject *)self);
@@ -898,6 +907,7 @@ font_init(PyFontObject *self, PyObject *args, PyObject *kwds)
     Py_XDECREF(oencoded);
     Py_DECREF(obj);
     self->font = font;
+    self->ttf_init_generation = current_ttf_generation;
     return 0;
 
 error:

diff --git a/src_c/include/pygame_font.h b/src_c/include/pygame_font.h
@@ -29,6 +29,7 @@ typedef struct {
   PyObject_HEAD
   TTF_Font* font;
   PyObject* weakreflist;
+  unsigned int ttf_init_generation;
 } PyFontObject;
 #define PyFont_AsFont(x) (((PyFontObject*)x)->font)
 

diff --git a/test/font_test.py b/test/font_test.py
@@ -206,6 +206,16 @@ def test_issue_font_alphablit(self):
 
         self.assertEqual(pre_blit_corner_pixel, post_blit_corner_pixel)
 
+    def test_segfault_after_reinit(self):
+        """ Reinitialization of font module should not cause
+            segmentation fault """
+        import gc
+        font = pygame_font.Font(None, 20)
+        pygame_font.quit()
+        pygame_font.init()
+        del font
+        gc.collect()
+
     def test_quit(self):
         pygame_font.quit()