Make sure datastack memory is freed after fork.

markshannon · markshannon · commit 2c149399eed8 · 2021-05-13T16:21:25.000+01:00
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
@@ -630,16 +630,18 @@ frame_dealloc(PyFrameObject *f)
     PyCodeObject *co = f->f_code;
 
     /* Kill all local variables */
-    if (f->f_own_locals_memory) {
+    if (f->f_localsptr) {
         for (int i = 0; i < co->co_nlocalsplus+FRAME_SPECIALS_SIZE; i++) {
             Py_CLEAR(f->f_localsptr[i]);
         }
         /* Free items on stack */
         for (int i = 0; i < f->f_stackdepth; i++) {
             Py_XDECREF(f->f_valuestack[i]);
         }
-        PyMem_Free(f->f_localsptr);
-        f->f_own_locals_memory = 0;
+        if (f->f_own_locals_memory) {
+            PyMem_Free(f->f_localsptr);
+            f->f_own_locals_memory = 0;
+        }
     }
     f->f_stackdepth = 0;
     Py_XDECREF(f->f_back);
diff --git a/Python/ceval.c b/Python/ceval.c
@@ -5179,7 +5179,6 @@ _PyEval_Vector(PyThreadState *tstate, PyFrameConstructor *con,
     */
     assert (!is_coro);
     assert(f->f_own_locals_memory == 0);
-    assert(f->f_stackdepth == 0);
     if (Py_REFCNT(f) > 1) {
         Py_DECREF(f);
         _PyObject_GC_TRACK(f);
@@ -5188,10 +5187,11 @@ _PyEval_Vector(PyThreadState *tstate, PyFrameConstructor *con,
         }
     }
     else {
+        ++tstate->recursion_depth;
+        f->f_localsptr = NULL;
         for (int i = 0; i < code->co_nlocalsplus + FRAME_SPECIALS_SIZE; i++) {
             Py_XDECREF(localsarray[i]);
         }
-        ++tstate->recursion_depth;
         Py_DECREF(f);
         --tstate->recursion_depth;
     }
diff --git a/Python/pystate.c b/Python/pystate.c
@@ -897,6 +897,13 @@ PyThreadState_Clear(PyThreadState *tstate)
     if (tstate->on_delete != NULL) {
         tstate->on_delete(tstate->on_delete_data);
     }
+    _PyStackChunk *chunk = tstate->datastack_chunk;
+    tstate->datastack_chunk = NULL;
+    while (chunk != NULL) {
+        _PyStackChunk *prev = chunk->previous;
+        _PyObject_VirtualFree(chunk, chunk->size);
+        chunk = prev;
+    }
 }
 
 
@@ -941,7 +948,6 @@ _PyThreadState_Delete(PyThreadState *tstate, int check_current)
         }
     }
     tstate_delete_common(tstate, gilstate);
-    _PyObject_VirtualFree(tstate->datastack_chunk, tstate->datastack_chunk->size);
     PyMem_RawFree(tstate);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -5179,7 +5179,6 @@ _PyEval_Vector(PyThreadState tstate, PyFrameConstructor con,`
`5179`	`5179`	`*/`
`5180`	`5180`	`assert (!is_coro);`
`5181`	`5181`	`assert(f->f_own_locals_memory == 0);`
`5182`		`- assert(f->f_stackdepth == 0);`
`5183`	`5182`	`if (Py_REFCNT(f) > 1) {`
`5184`	`5183`	`Py_DECREF(f);`
`5185`	`5184`	`_PyObject_GC_TRACK(f);`
`@@ -5188,10 +5187,11 @@ _PyEval_Vector(PyThreadState tstate, PyFrameConstructor con,`
`5188`	`5187`	`}`
`5189`	`5188`	`}`
`5190`	`5189`	`else {`
	`5190`	`+ ++tstate->recursion_depth;`
	`5191`	`+ f->f_localsptr = NULL;`
`5191`	`5192`	`for (int i = 0; i < code->co_nlocalsplus + FRAME_SPECIALS_SIZE; i++) {`
`5192`	`5193`	`Py_XDECREF(localsarray[i]);`
`5193`	`5194`	`}`
`5194`		`- ++tstate->recursion_depth;`
`5195`	`5195`	`Py_DECREF(f);`
`5196`	`5196`	`--tstate->recursion_depth;`
`5197`	`5197`	`}`
Original file line number	Diff line number	Diff line change
`@@ -897,6 +897,13 @@ PyThreadState_Clear(PyThreadState *tstate)`
`897`	`897`	`if (tstate->on_delete != NULL) {`
`898`	`898`	`tstate->on_delete(tstate->on_delete_data);`
`899`	`899`	`}`
	`900`	`+ _PyStackChunk *chunk = tstate->datastack_chunk;`
	`901`	`+ tstate->datastack_chunk = NULL;`
	`902`	`+ while (chunk != NULL) {`
	`903`	`+ _PyStackChunk *prev = chunk->previous;`
	`904`	`+ _PyObject_VirtualFree(chunk, chunk->size);`
	`905`	`+ chunk = prev;`
	`906`	`+ }`
`900`	`907`	`}`
`901`	`908`
`902`	`909`
`@@ -941,7 +948,6 @@ _PyThreadState_Delete(PyThreadState *tstate, int check_current)`
`941`	`948`	`}`
`942`	`949`	`}`
`943`	`950`	`tstate_delete_common(tstate, gilstate);`
`944`		`- _PyObject_VirtualFree(tstate->datastack_chunk, tstate->datastack_chunk->size);`
`945`	`951`	`PyMem_RawFree(tstate);`
`946`	`952`	`}`
`947`	`953`