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().
- 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().
- 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.
- 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
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.
- 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.
- 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.
- 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.
+ 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
* 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)
}
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 */
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