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[Bug python/10896] New: gdb python hooks leak struct value *s
- From: "gdb at tmm1 dot net" <sourceware-bugzilla at sourceware dot org>
- To: gdb-prs at sourceware dot org
- Date: 3 Nov 2009 03:25:59 -0000
- Subject: [Bug python/10896] New: gdb python hooks leak struct value *s
- Reply-to: sourceware-bugzilla at sourceware dot org
$ cat simple.c
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
struct blah {
char test[2];
int i;
float none;
} *list_of_blahs;
int main(){
list_of_blahs = malloc(sizeof(struct blah) * 2000000);
printf("pid: %d\n", getpid());
while(1){
sleep(1);
}
}
$ cat simple.py
gdb.execute('p list_of_blahs')
list = gdb.history(0)
end = list + 1000000
while list < end:
list['i']
list += 1
gdb will leak a large amount of memory while executing the python loop. Some (but not all) of this
memory is returned after the loop completes and free_all_values() is called for the next command. The
following patch keeps the memory usage constant during the loop:
diff --git a/python/py-value.c b/python/py-value.c
index 8f8c610..c3a6cbf 100644
--- a/python/py-value.c
+++ b/python/py-value.c
@@ -139,7 +139,7 @@ valpy_new (PyTypeObject *subtype, PyObject *args, PyObject *keywords)
}
value_obj->value = value;
- value_incref (value);
+ release_value_or_incref (value);
value_obj->address = NULL;
value_obj->type = NULL;
note_value (value_obj);
@@ -263,6 +263,7 @@ valpy_cast (PyObject *self, PyObject *args)
{
PyObject *type_obj;
struct type *type;
+ PyObject *res_obj = NULL;
struct value *res_val = NULL; /* Initialize to appease gcc warning. */
volatile struct gdb_exception except;
@@ -301,8 +302,10 @@ valpy_getitem (PyObject *self, PyObject *key)
{
value_object *self_value = (value_object *) self;
char *field = NULL;
+ PyObject *res_obj = NULL;
struct value *res_val = NULL;
volatile struct gdb_exception except;
+ struct value *mark = value_mark ();
if (gdbpy_is_string (key))
{
@@ -340,9 +343,13 @@ valpy_getitem (PyObject *self, PyObject *key)
}
xfree (field);
- GDB_PY_HANDLE_EXCEPTION (except);
+ GDB_PY_HANDLE_EXCEPTION_AND_CLEANUP (except, mark);
+
+ if (res_val)
+ res_obj = value_to_value_object (res_val);
- return res_val ? value_to_value_object (res_val) : NULL;
+ value_free_to_mark (mark);
+ return res_obj;
}
static int
@@ -423,8 +430,10 @@ enum valpy_opcode
static PyObject *
valpy_binop (enum valpy_opcode opcode, PyObject *self, PyObject *other)
{
+ PyObject *res_obj = NULL;
struct value *res_val = NULL; /* Initialize to appease gcc warning. */
volatile struct gdb_exception except;
+ struct value *mark = value_mark ();
TRY_CATCH (except, RETURN_MASK_ALL)
{
@@ -515,9 +524,13 @@ valpy_binop (enum valpy_opcode opcode, PyObject *self, PyObject *other)
break;
}
}
- GDB_PY_HANDLE_EXCEPTION (except);
+ GDB_PY_HANDLE_EXCEPTION_AND_CLEANUP (except, mark);
+
+ if (res_val)
+ res_obj = value_to_value_object (res_val);
- return res_val ? value_to_value_object (res_val) : NULL;
+ value_free_to_mark (mark);
+ return res_obj;
}
static PyObject *
@@ -680,6 +693,7 @@ valpy_richcompare (PyObject *self, PyObject *other, int op)
int result = 0;
struct value *value_other;
volatile struct gdb_exception except;
+ struct value *mark = value_mark ();
if (other == Py_None)
/* Comparing with None is special. From what I can tell, in Python
@@ -738,6 +752,7 @@ valpy_richcompare (PyObject *self, PyObject *other, int op)
break;
}
}
+ value_free_to_mark (mark);
GDB_PY_HANDLE_EXCEPTION (except);
/* In this case, the Python exception has already been set. */
@@ -858,7 +873,7 @@ value_to_value_object (struct value *val)
if (val_obj != NULL)
{
val_obj->value = val;
- value_incref (val);
+ release_value_or_incref (val);
val_obj->address = NULL;
val_obj->type = NULL;
note_value (val_obj);
diff --git a/python/python-internal.h b/python/python-internal.h
index fa4a62b..bc9c8c0 100644
--- a/python/python-internal.h
+++ b/python/python-internal.h
@@ -103,11 +103,17 @@ extern const struct language_defn *python_language;
/* Use this after a TRY_EXCEPT to throw the appropriate Python
exception. */
#define GDB_PY_HANDLE_EXCEPTION(Exception) \
+ GDB_PY_HANDLE_EXCEPTION_AND_CLEANUP(Exception, NULL)
+
+#define GDB_PY_HANDLE_EXCEPTION_AND_CLEANUP(Exception, mark) \
do { \
- if (Exception.reason < 0) \
+ if (Exception.reason < 0) { \
+ if (mark) \
+ value_free_to_mark (mark); \
return PyErr_Format (Exception.reason == RETURN_QUIT \
? PyExc_KeyboardInterrupt : PyExc_RuntimeError, \
"%s", Exception.message); \
+ } \
} while (0)
diff --git a/value.c b/value.c
index 589e03b..59a0196 100644
--- a/value.c
+++ b/value.c
@@ -675,7 +675,7 @@ free_all_values (void)
/* Remove VAL from the chain all_values
so it will not be freed automatically. */
-void
+int
release_value (struct value *val)
{
struct value *v;
@@ -683,7 +683,7 @@ release_value (struct value *val)
if (all_values == val)
{
all_values = val->next;
- return;
+ return 1;
}
for (v = all_values; v; v = v->next)
@@ -691,9 +691,21 @@ release_value (struct value *val)
if (v->next == val)
{
v->next = val->next;
- break;
+ return 1;
}
}
+
+ return 0;
+}
+
+/* Release VAL or increment its reference count if
+ it was released already */
+
+void
+release_value_or_incref (struct value *val)
+{
+ if (release_value (val) == 0)
+ value_incref (val);
}
/* Release all values up to mark */
diff --git a/value.h b/value.h
index 51e6960..4760c4a 100644
--- a/value.h
+++ b/value.h
@@ -594,7 +594,9 @@ extern void value_free (struct value *val);
extern void free_all_values (void);
-extern void release_value (struct value *val);
+extern int release_value (struct value *val);
+
+extern void release_value_or_incref (struct value *val);
extern int record_latest_value (struct value *val);
--
Summary: gdb python hooks leak struct value *s
Product: gdb
Version: 7.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: python
AssignedTo: unassigned at sourceware dot org
ReportedBy: gdb at tmm1 dot net
CC: gdb-prs at sourceware dot org
http://sourceware.org/bugzilla/show_bug.cgi?id=10896
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