bpo-46430: Fix memory leak in interned strings of deep-frozen modules (GH-31549)

kumaraditya303 · web-flow · commit 4dc746310bd3 · 2022-02-24T17:54:06.000+01:00
diff --git a/Include/internal/pycore_pylifecycle.h b/Include/internal/pycore_pylifecycle.h
@@ -65,7 +65,7 @@ extern PyStatus _Py_HashRandomization_Init(const PyConfig *);
 extern PyStatus _PyImportZip_Init(PyThreadState *tstate);
 extern PyStatus _PyGC_Init(PyInterpreterState *interp);
 extern PyStatus _PyAtExit_Init(PyInterpreterState *interp);
-
+extern void _Py_Deepfreeze_Init(void);
 
 /* Various internal finalizers */
 
diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-02-24-07-33-29.bpo-46430.c91TAg.rst b/Misc/NEWS.d/next/Core and Builtins/2022-02-24-07-33-29.bpo-46430.c91TAg.rst
@@ -0,0 +1 @@
+Fix memory leak in interned strings of deep-frozen modules.
diff --git a/Programs/_bootstrap_python.c b/Programs/_bootstrap_python.c
@@ -14,9 +14,13 @@
 #include "Python/frozen_modules/importlib._bootstrap_external.h"
 /* End includes */
 
-/* Empty finalizer for deepfrozen modules*/
+/* Empty initializer for deepfrozen modules */
+void _Py_Deepfreeze_Init(void)
+{
+}
+/* Empty finalizer for deepfrozen modules */
 void
-_Py_Deepfreeze_Fini(void) 
+_Py_Deepfreeze_Fini(void)
 {
 }
 
diff --git a/Programs/_freeze_module.c b/Programs/_freeze_module.c
@@ -22,6 +22,10 @@
 #include <unistd.h>
 #endif
 
+/* Empty initializer for deepfrozen modules */
+void _Py_Deepfreeze_Init(void)
+{
+}
 /* Empty finalizer for deepfrozen modules */
 void
 _Py_Deepfreeze_Fini(void)
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
@@ -754,7 +754,6 @@ pycore_init_types(PyInterpreterState *interp)
     if (_PyStatus_EXCEPTION(status)) {
         return status;
     }
-
     return _PyStatus_OK();
 }
 
@@ -827,7 +826,10 @@ pycore_interp_init(PyThreadState *tstate)
     if (_PyStatus_EXCEPTION(status)) {
         return status;
     }
-
+    // Intern strings in deep-frozen modules first so that others
+    // can use it instead of creating a heap allocated string.
+    _Py_Deepfreeze_Init();
+    
     status = pycore_init_types(interp);
     if (_PyStatus_EXCEPTION(status)) {
         goto done;
diff --git a/Tools/scripts/deepfreeze.py b/Tools/scripts/deepfreeze.py
@@ -110,6 +110,7 @@ def __init__(self, file: TextIO) -> None:
         self.hits, self.misses = 0, 0
         self.patchups: list[str] = []
         self.deallocs: list[str] = []
+        self.interns: list[str] = []
         self.write('#include "Python.h"')
         self.write('#include "internal/pycore_gc.h"')
         self.write('#include "internal/pycore_code.h"')
@@ -279,7 +280,7 @@ def generate_code(self, name: str, code: types.CodeType) -> str:
             self.write(f".co_cellvars = {co_cellvars},")
             self.write(f".co_freevars = {co_freevars},")
         self.deallocs.append(f"_PyStaticCode_Dealloc(&{name});")
-        self.patchups.append(f"_PyStaticCode_InternStrings(&{name});")
+        self.interns.append(f"_PyStaticCode_InternStrings(&{name});")
         return f"& {name}.ob_base"
 
     def generate_tuple(self, name: str, t: Tuple[object, ...]) -> str:
@@ -446,6 +447,9 @@ def generate(args: list[str], output: TextIO) -> None:
     with printer.block(f"void\n_Py_Deepfreeze_Fini(void)"):
             for p in printer.deallocs:
                 printer.write(p)
+    with printer.block(f"void\n_Py_Deepfreeze_Init(void)"):
+            for p in printer.interns:
+                printer.write(p)
     if verbose:
         print(f"Cache hits: {printer.hits}, misses: {printer.misses}")
 

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+Fix memory leak in interned strings of deep-frozen modules.`
Original file line number	Diff line number	Diff line change
`@@ -14,9 +14,13 @@`
`14`	`14`	`#include "Python/frozen_modules/importlib._bootstrap_external.h"`
`15`	`15`	`/* End includes */`
`16`	`16`
`17`		`-/* Empty finalizer for deepfrozen modules*/`
	`17`	`+/* Empty initializer for deepfrozen modules */`
	`18`	`+void _Py_Deepfreeze_Init(void)`
	`19`	`+{`
	`20`	`+}`
	`21`	`+/* Empty finalizer for deepfrozen modules */`
`18`	`22`	`void`
`19`		`-_Py_Deepfreeze_Fini(void)`
	`23`	`+_Py_Deepfreeze_Fini(void)`
`20`	`24`	`{`
`21`	`25`	`}`
`22`	`26`
Original file line number	Diff line number	Diff line change
`@@ -754,7 +754,6 @@ pycore_init_types(PyInterpreterState *interp)`
`754`	`754`	`if (_PyStatus_EXCEPTION(status)) {`
`755`	`755`	`return status;`
`756`	`756`	`}`
`757`		`-`
`758`	`757`	`return _PyStatus_OK();`
`759`	`758`	`}`
`760`	`759`
`@@ -827,7 +826,10 @@ pycore_interp_init(PyThreadState *tstate)`
`827`	`826`	`if (_PyStatus_EXCEPTION(status)) {`
`828`	`827`	`return status;`
`829`	`828`	`}`
`830`		`-`
	`829`	`+ // Intern strings in deep-frozen modules first so that others`
	`830`	`+ // can use it instead of creating a heap allocated string.`
	`831`	`+ _Py_Deepfreeze_Init();`
	`832`	`+`
`831`	`833`	`status = pycore_init_types(interp);`
`832`	`834`	`if (_PyStatus_EXCEPTION(status)) {`
`833`	`835`	`goto done;`