diff options
Diffstat (limited to 'Objects')
| -rw-r--r-- | Objects/object.c | 9 | ||||
| -rw-r--r-- | Objects/obmalloc.c | 9 |
2 files changed, 10 insertions, 8 deletions
diff --git a/Objects/object.c b/Objects/object.c index c9aa479..3fad73c 100644 --- a/Objects/object.c +++ b/Objects/object.c @@ -415,13 +415,12 @@ _Py_BreakPoint(void) } -/* Heuristic checking if the object memory has been deallocated. - Rely on the debug hooks on Python memory allocators which fills the memory - with DEADBYTE (0xDB) when memory is deallocated. +/* Heuristic checking if the object memory is uninitialized or deallocated. + Rely on the debug hooks on Python memory allocators: + see _PyMem_IsPtrFreed(). The function can be used to prevent segmentation fault on dereferencing - pointers like 0xdbdbdbdbdbdbdbdb. Such pointer is very unlikely to be mapped - in memory. */ + pointers like 0xDDDDDDDDDDDDDDDD. */ int _PyObject_IsFreed(PyObject *op) { diff --git a/Objects/obmalloc.c b/Objects/obmalloc.c index e919fad..be43c7a 100644 --- a/Objects/obmalloc.c +++ b/Objects/obmalloc.c @@ -1915,13 +1915,16 @@ _Py_GetAllocatedBlocks(void) /* Special bytes broadcast into debug memory blocks at appropriate times. * Strings of these are unlikely to be valid addresses, floats, ints or * 7-bit ASCII. If modified, _PyMem_IsPtrFreed() should be updated as well. + * + * Byte patterns 0xCB, 0xBB and 0xFB have been replaced with 0xCD, 0xDD and + * 0xFD to use the same values than Windows CRT debug malloc() and free(). */ #undef CLEANBYTE #undef DEADBYTE #undef FORBIDDENBYTE -#define CLEANBYTE 0xCB /* clean (newly allocated) memory */ -#define DEADBYTE 0xDB /* dead (newly freed) memory */ -#define FORBIDDENBYTE 0xFB /* untouchable bytes at each end of a block */ +#define CLEANBYTE 0xCD /* clean (newly allocated) memory */ +#define DEADBYTE 0xDD /* dead (newly freed) memory */ +#define FORBIDDENBYTE 0xFD /* untouchable bytes at each end of a block */ static size_t serialno = 0; /* incremented on each debug {m,re}alloc */ |