X gc.collect on loadblk -> pybuf.ob_refcnt != 1

bigfile/_bigfile.c

@@ -53,6 +53,7 @@ typedef struct _frame PyFrameObject;
 
 void PyBufferObject_Unpin(PyBufferObject *bufo);
 void PyBuffer_Unpin(Py_buffer *view);
+static PyObject *gcmodule;
 
 
 /*
@@ -560,6 +561,19 @@ out:
     if (pybuf)
         BUG_ON(pybuf->ob_refcnt != 1);
 #endif
+    if (pybuf && pybuf->ob_refcnt != 1) {
+        PyObject *pybuf_users = PyObject_CallMethod(gcmodule, "get_referrers", "O", pybuf);
+        BUG_ON(!pybuf_users);
+        //PyObject_Repr(pybuf_users);
+        fprintf(stderr, "\n");
+        _PyObject_Dump(pybuf_users);
+        fprintf(stderr, "\n");
+        PyObject_Print(pybuf_users, stderr, 0);
+        fprintf(stderr, "curexc_tb:\t%p\n", x_curexc_traceback);
+        fprintf(stderr, "exc_tb:\t%p\n", x_exc_traceback);
+        Py_DECREF(pybuf_users);
+        BUG();
+    }
 
     /* drop pybuf
      *
@@ -911,6 +925,11 @@ _init_bigfile(void)
     CSTi(WRITEOUT_STORE);
     CSTi(WRITEOUT_MARKSTORED);
 
+    /* import gc */
+    gcmodule = PyImport_ImportModule("gc");
+    if (!gcmodule)
+        return NULL;
+
     return m;
 }
 

bigfile/tests/test_basic.py

@@ -124,6 +124,21 @@ def test_basic():
     # TODO close f
 
 
+def zzz():
+    try:
+        1/0
+    except ZeroDivisionError:
+        pass
+
+    exc_type, exc_value, exc_traceback = sys.exc_info()
+    if PY2:
+        assert exc_type is ZeroDivisionError
+    else:
+        # on python3 exception state is cleared upon exiting from `except`
+        assert exc_type is None
+
+    # del exc_traceback
+
 # test that python exception state is preserved across pagefaulting
 def test_pagefault_savestate():
     class BadFile(BigFile):
@@ -159,12 +174,23 @@ def test_pagefault_savestate():
             # # gc.collect() which cannot be perform in pagefault handler.
             # #
             # # Not breaking this loop will BUG with `buf.refcnt != 1` on return
-            # del exc_traceback
+            del exc_traceback
+
+            zzz()
 
+            raise Exception('eee')
             assert len(buf) > 0
 
             self.loadblk_run = 1
-            self.loadblk_buf = buf
+            #self.loadblk_buf = buf
+            #self.loadblk_buf2 = buffer(buf)
+            #self.loadblk_mbuf = memoryview(buf)
+            #print
+            #print
+            #print '111'
+            #print `buf`
+            #print `self.loadblk_buf2`
+            #print `self.loadblk_mbuf`
 
 
     f   = BadFile(PS)
@@ -189,7 +215,14 @@ def test_pagefault_savestate():
         assert exc_tb    is exc_tb2
 
         # TODO check f.loadblk_buf for access -- len=0, read/write - index error
+        print
+        print '222'
+        print `f.loadblk_buf`
+        print `f.loadblk_buf2`
+        print `f.loadblk_mbuf`
         assert len(f.loadblk_buf) == 0
+        assert len(f.loadblk_buf2) == 0
+        assert len(f.loadblk_mbuf) == 0
         raises(IndexError, "f.loadblk_buf[0]")
         raises(IndexError, "f.loadblk_buf[0] = b'1'")