From: Tony Solomonik <tony.solomonik@gmail.com>
Date: Sun, 30 Aug 2020 04:53:08 +0000 (+0300)
Subject: closes bpo-41533: Fix a potential memory leak when allocating a stack (GH-21847)
X-Git-Tag: v3.10.0a1~212
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=75c80b0bda89debf312f075716b8c467d411f90e;p=thirdparty%2FPython%2Fcpython.git

closes bpo-41533: Fix a potential memory leak when allocating a stack (GH-21847)

Free the stack allocated in va_build_stack if do_mkstack fails
and the stack is not a small_stack
---

diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-08-12-20-29-57.bpo-41533.4pcVAc.rst b/Misc/NEWS.d/next/Core and Builtins/2020-08-12-20-29-57.bpo-41533.4pcVAc.rst
new file mode 100644
index 000000000000..e166f0c0b621
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-08-12-20-29-57.bpo-41533.4pcVAc.rst	
@@ -0,0 +1,2 @@
+Free the stack allocated in ``va_build_stack`` if ``do_mkstack`` fails and
+the stack is not a ``small_stack``.
diff --git a/Python/modsupport.c b/Python/modsupport.c
index 2637039d4a15..2dabcf383409 100644
--- a/Python/modsupport.c
+++ b/Python/modsupport.c
@@ -622,6 +622,9 @@ va_build_stack(PyObject **small_stack, Py_ssize_t small_stack_len,
     va_end(lva);
 
     if (res < 0) {
+        if (stack != small_stack) {
+            PyMem_Free(stack);
+        }
         return NULL;
     }