gh-149816: add missing critical section on self in buffered_iternext (#150295)

kumaraditya303 · web-flow · commit e8545ed3eafb · 2026-05-23T08:57:13.000Z
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
@@ -1509,7 +1509,9 @@ buffered_iternext(PyObject *op)
         tp == state->PyBufferedRandom_Type)
     {
         /* Skip method call overhead for speed */
+        Py_BEGIN_CRITICAL_SECTION(self);
         line = _buffered_readline(self, -1);
+        Py_END_CRITICAL_SECTION();
     }
     else {
         line = PyObject_CallMethodNoArgs((PyObject *)self,

Original file line number	Diff line number	Diff line change
`@@ -1509,7 +1509,9 @@ buffered_iternext(PyObject *op)`
`1509`	`1509`	`tp == state->PyBufferedRandom_Type)`
`1510`	`1510`	`{`
`1511`	`1511`	`/* Skip method call overhead for speed */`
	`1512`	`+ Py_BEGIN_CRITICAL_SECTION(self);`
`1512`	`1513`	`line = _buffered_readline(self, -1);`
	`1514`	`+ Py_END_CRITICAL_SECTION();`
`1513`	`1515`	`}`
`1514`	`1516`	`else {`
`1515`	`1517`	`line = PyObject_CallMethodNoArgs((PyObject *)self,`