[3.13] gh-151112: Fix double free in assemble_init when out of memory (GH-151142) (#151207)

miss-islington · StanFromIreland · web-flow · commit 310125eb9d30 · 2026-06-09T21:13:40.000+01:00
gh-151112: Fix double free in `assemble_init` when out of memory (GH-151142) (cherry picked from commit 5804991) Co-authored-by: Stan Ulbrych <stan@python.org>
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-06-09-12-24-35.gh-issue-151112.4RKCkD.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-06-09-12-24-35.gh-issue-151112.4RKCkD.rst
@@ -0,0 +1 @@
+Fix a crash in the compiler that could occur when running out of memory.
diff --git a/Python/assemble.c b/Python/assemble.c
@@ -80,9 +80,9 @@ assemble_init(struct assembler *a, int firstlineno)
     }
     return SUCCESS;
 error:
-    Py_XDECREF(a->a_bytecode);
-    Py_XDECREF(a->a_linetable);
-    Py_XDECREF(a->a_except_table);
+    Py_CLEAR(a->a_bytecode);
+    Py_CLEAR(a->a_linetable);
+    Py_CLEAR(a->a_except_table);
     return ERROR;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+Fix a crash in the compiler that could occur when running out of memory.`
Original file line number	Diff line number	Diff line change
`@@ -80,9 +80,9 @@ assemble_init(struct assembler *a, int firstlineno)`
`80`	`80`	`}`
`81`	`81`	`return SUCCESS;`
`82`	`82`	`error:`
`83`		`- Py_XDECREF(a->a_bytecode);`
`84`		`- Py_XDECREF(a->a_linetable);`
`85`		`- Py_XDECREF(a->a_except_table);`
	`83`	`+ Py_CLEAR(a->a_bytecode);`
	`84`	`+ Py_CLEAR(a->a_linetable);`
	`85`	`+ Py_CLEAR(a->a_except_table);`
`86`	`86`	`return ERROR;`
`87`	`87`	`}`
`88`	`88`