fix [#28114] Render Crash
authorCampbell Barton <ideasman42@gmail.com>
Thu, 4 Aug 2011 01:56:36 +0000 (01:56 +0000)
committerCampbell Barton <ideasman42@gmail.com>
Thu, 4 Aug 2011 01:56:36 +0000 (01:56 +0000)
existing check for driver to use GIL was not thread safe and could cause, details in the report.

This bug was caused by a check to avoid hanging, a fix for [#27683] that worked in 2.4x because the UI didn't use python to draw while rendering.

Apply a different fix for [#27683], when calling an operator, call PyEval_SaveThread(), then PyEval_RestoreThread() so the GIL can be aquired by threads started by the operator - in this case bake starting a thread that evaluates drivers.

source/blender/python/intern/bpy_driver.c
source/blender/python/intern/bpy_operator.c

index bcd5df97c2ce4bb262eb2f1823e225a365bb5a1f..d68fd9a9111dcf5038c9ba96c8d3eee3c8561de0 100644 (file)
@@ -41,8 +41,6 @@
 
 #include "bpy_driver.h"
 
-#include "../generic/py_capi_utils.h"
-
 /* for pydrivers (drivers using one-line Python expressions to express relationships between targets) */
 PyObject *bpy_pydriver_Dict= NULL;
 
@@ -89,7 +87,7 @@ int bpy_pydriver_create_dict(void)
 void BPY_driver_reset(void)
 {
        PyGILState_STATE gilstate;
-       int use_gil= !PYC_INTERPRETER_ACTIVE;
+       int use_gil= 1; /* !PYC_INTERPRETER_ACTIVE; */
 
        if(use_gil)
                gilstate= PyGILState_Ensure();
@@ -120,9 +118,14 @@ static void pydriver_error(ChannelDriver *driver)
 /* This evals py driver expressions, 'expr' is a Python expression that
  * should evaluate to a float number, which is returned.
  *
- * note: PyGILState_Ensure() isnt always called because python can call the
- * bake operator which intern starts a thread which calls scene update which
- * does a driver update. to avoid a deadlock check PYC_INTERPRETER_ACTIVE if PyGILState_Ensure() is needed.
+ * (old)note: PyGILState_Ensure() isnt always called because python can call
+ * the bake operator which intern starts a thread which calls scene update
+ * which does a driver update. to avoid a deadlock check PYC_INTERPRETER_ACTIVE
+ * if PyGILState_Ensure() is needed - see [#27683]
+ *
+ * (new)note: checking if python is running is not threadsafe [#28114]
+ * now release the GIL on python operator execution instead, using
+ * PyEval_SaveThread() / PyEval_RestoreThread() so we dont lock up blender.
  */
 float BPY_driver_exec(ChannelDriver *driver)
 {
@@ -149,7 +152,7 @@ float BPY_driver_exec(ChannelDriver *driver)
                return 0.0f;
        }
 
-       use_gil= !PYC_INTERPRETER_ACTIVE;
+       use_gil= 1; /* !PYC_INTERPRETER_ACTIVE; */
 
        if(use_gil)
                gilstate= PyGILState_Ensure();
index b8883e655f284efb0c1717a98cda22e94093c2f2..4a17c45ae3884bcf3904862afe5d8c4c8f66949f 100644 (file)
 #include "BKE_report.h"
 #include "BKE_context.h"
 
+/* so operators called can spawn threads which aquire the GIL */
+#define BPY_RELEASE_GIL
+
+
 static PyObject *pyop_poll(PyObject *UNUSED(self), PyObject *args)
 {
        wmOperatorType *ot;
@@ -219,7 +223,22 @@ static PyObject *pyop_call(PyObject *UNUSED(self), PyObject *args)
                        reports= MEM_mallocN(sizeof(ReportList), "wmOperatorReportList");
                        BKE_reports_init(reports, RPT_STORE | RPT_OP_HOLD); /* own so these dont move into global reports */
 
-                       operator_ret= WM_operator_call_py(C, ot, context, &ptr, reports);
+#ifdef BPY_RELEASE_GIL
+                       /* release GIL, since a thread could be started from an operator
+                        * that updates a driver */
+                       /* note: I havve not seen any examples of code that does this
+                        * so it may not be officially supported but seems to work ok. */
+                       {
+                               PyThreadState *ts= PyEval_SaveThread();
+#endif
+
+                               operator_ret= WM_operator_call_py(C, ot, context, &ptr, reports);
+
+#ifdef BPY_RELEASE_GIL
+                               /* regain GIL */
+                               PyEval_RestoreThread(ts);
+                       }
+#endif
 
                        error_val= BPy_reports_to_error(reports, PyExc_RuntimeError, FALSE);