diff options
| -rw-r--r-- | Misc/NEWS | 25 | ||||
| -rw-r--r-- | Objects/obmalloc.c | 50 |
2 files changed, 40 insertions, 35 deletions
@@ -12,6 +12,15 @@ What's New in Python 2.5 alpha 1? Core and builtins ----------------- +- SF bug #1185883: Python's small-object memory allocator took over + a block managed by the platform C library whenever a realloc specified + a small new size. However, there's no portable way to know then how + much of the address space following the pointer is valid, so no + portable way to copy data from the C-managed block into Python's + small-object space without risking a memory fault. Python's small-object + realloc now leaves such blocks under the control of the platform C + realloc. + - SF bug #1232517: An overflow error was not detected properly when attempting to convert a large float to an int in os.utime(). @@ -59,7 +68,7 @@ Core and builtins - Bug #1165306: instancemethod_new allowed the creation of a method with im_class == im_self == NULL, which caused a crash when called. -- Move exception finalisation later in the shutdown process - this +- Move exception finalisation later in the shutdown process - this fixes the crash seen in bug #1165761 - Added two new builtins, any() and all(). @@ -74,7 +83,7 @@ Core and builtins - Bug #1155938: new style classes did not check that __init__() was returning None. -- Patch #802188: Report characters after line continuation character +- Patch #802188: Report characters after line continuation character ('\') with a specific error message. - Bug #723201: Raise a TypeError for passing bad objects to 'L' format. @@ -82,7 +91,7 @@ Core and builtins - Bug #1124295: the __name__ attribute of file objects was inadvertently made inaccessible in restricted mode. -- Bug #1074011: closing sys.std{out,err} now causes a flush() and +- Bug #1074011: closing sys.std{out,err} now causes a flush() and an ferror() call. - min() and max() now support key= arguments with the same meaning as in @@ -103,7 +112,7 @@ Core and builtins Extension Modules ----------------- -- Bug #1234979: For the argument of thread.Lock.acquire, the Windows +- Bug #1234979: For the argument of thread.Lock.acquire, the Windows implemented treated all integer values except 1 as false. - Bug #1194181: bz2.BZ2File didn't handle mode 'U' correctly. @@ -128,7 +137,7 @@ Extension Modules - Patches #925152, #1118602: Avoid reading after the end of the buffer in pyexpat.GetInputContext. -- Patches #749830, #1144555: allow UNIX mmap size to default to current +- Patches #749830, #1144555: allow UNIX mmap size to default to current file size. - Added functional.partial(). See PEP309. @@ -201,7 +210,7 @@ Library - Bug #1163325: Decimal infinities failed to hash. Attempting to hash a NaN raised an InvalidOperation instead of a TypeError. -- Patch #918101: Add tarfile open mode r|* for auto-detection of the +- Patch #918101: Add tarfile open mode r|* for auto-detection of the stream compression; add, for symmetry reasons, r:* as a synonym of r. - Patch #1043890: Add extractall method to tarfile. @@ -212,7 +221,7 @@ Library - Patch #1103407: Properly deal with tarfile iterators when untarring symbolic links on Windows. -- Patch #645894: Use getrusage for computing the time consumption in +- Patch #645894: Use getrusage for computing the time consumption in profile.py if available. - Patch #1046831: Use get_python_version where appropriate in sysconfig.py. @@ -250,7 +259,7 @@ Library + Dialects are now validated by the underlying C code, better reflecting it's capabilities, and improving it's compliance with - PEP 305. + PEP 305. + Dialect parameter parsing has been re-implemented to improve error reporting. + quotechar=None and quoting=QUOTE_NONE now work the way PEP 305 diff --git a/Objects/obmalloc.c b/Objects/obmalloc.c index 7b629b8..a6fdf40 100644 --- a/Objects/obmalloc.c +++ b/Objects/obmalloc.c @@ -139,9 +139,9 @@ * getpagesize() call or deduced from various header files. To make * things simpler, we assume that it is 4K, which is OK for most systems. * It is probably better if this is the native page size, but it doesn't - * have to be. In theory, if SYSTEM_PAGE_SIZE is larger than the native page - * size, then `POOL_ADDR(p)->arenaindex' could rarely cause a segmentation - * violation fault. 4K is apparently OK for all the platforms that python + * have to be. In theory, if SYSTEM_PAGE_SIZE is larger than the native page + * size, then `POOL_ADDR(p)->arenaindex' could rarely cause a segmentation + * violation fault. 4K is apparently OK for all the platforms that python * currently targets. */ #define SYSTEM_PAGE_SIZE (4 * 1024) @@ -841,30 +841,26 @@ PyObject_Realloc(void *p, size_t nbytes) } return bp; } - /* We're not managing this block. */ - if (nbytes <= SMALL_REQUEST_THRESHOLD) { - /* Take over this block -- ask for at least one byte so - * we really do take it over (PyObject_Malloc(0) goes to - * the system malloc). - */ - bp = PyObject_Malloc(nbytes ? nbytes : 1); - if (bp != NULL) { - memcpy(bp, p, nbytes); - free(p); - } - else if (nbytes == 0) { - /* Meet the doc's promise that nbytes==0 will - * never return a NULL pointer when p isn't NULL. - */ - bp = p; - } - - } - else { - assert(nbytes != 0); - bp = realloc(p, nbytes); - } - return bp; + /* We're not managing this block. If nbytes <= + * SMALL_REQUEST_THRESHOLD, it's tempting to try to take over this + * block. However, if we do, we need to copy the valid data from + * the C-managed block to one of our blocks, and there's no portable + * way to know how much of the memory space starting at p is valid. + * As bug 1185883 pointed out the hard way, it's possible that the + * C-managed block is "at the end" of allocated VM space, so that + * a memory fault can occur if we try to copy nbytes bytes starting + * at p. Instead we punt: let C continue to manage this block. + */ + if (nbytes) + return realloc(p, nbytes); + /* C doesn't define the result of realloc(p, 0) (it may or may not + * return NULL then), but Python's docs promise that nbytes==0 never + * returns NULL. We don't pass 0 to realloc(), to avoid that endcase + * to begin with. Even then, we can't be sure that realloc() won't + * return NULL. + */ + bp = realloc(p, 1); + return bp ? bp : p; } #else /* ! WITH_PYMALLOC */ |