Issue #7084: Fix a (very unlikely) crash when printing a list from one
thread, and mutating it from another one. Patch by Scott Dial.
diff --git a/Misc/ACKS b/Misc/ACKS
index 6383a46..c8f80e6 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -175,6 +175,7 @@
Erik Demaine
Roger Dev
Raghuram Devarakonda
+Scott Dial
Toby Dickenson
Mark Dickinson
Jack Diederich
diff --git a/Misc/NEWS b/Misc/NEWS
index 42a8cd9..9fc3edc 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
Core and Builtins
-----------------
+- Issue #7084: Fix a (very unlikely) crash when printing a list from one
+ thread, and mutating it from another one. Patch by Scott Dial.
+
- Issue #1571184: The Unicode database contains properties for more characters.
The tables for code points representing numeric values, white spaces or line
breaks are now generated from the official Unicode Character Database files,
diff --git a/Objects/listobject.c b/Objects/listobject.c
index 98d7e47..c5b1475 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -319,6 +319,7 @@
{
int rc;
Py_ssize_t i;
+ PyObject *item;
rc = Py_ReprEnter((PyObject*)op);
if (rc != 0) {
@@ -333,15 +334,19 @@
fprintf(fp, "[");
Py_END_ALLOW_THREADS
for (i = 0; i < Py_SIZE(op); i++) {
+ item = op->ob_item[i];
+ Py_INCREF(item);
if (i > 0) {
Py_BEGIN_ALLOW_THREADS
fprintf(fp, ", ");
Py_END_ALLOW_THREADS
}
- if (PyObject_Print(op->ob_item[i], fp, 0) != 0) {
+ if (PyObject_Print(item, fp, 0) != 0) {
+ Py_DECREF(item);
Py_ReprLeave((PyObject *)op);
return -1;
}
+ Py_DECREF(item);
}
Py_BEGIN_ALLOW_THREADS
fprintf(fp, "]");