-fno-omit-frame-pointer is not enough to make every target walkable by the
simple manual frame pointer unwinder.
The helper used by test_frame_pointer_unwind used to assume the frame pointer
named a two-word record where fp[0] was the previous frame pointer and fp[1]
was the return address. That is only the generic layout used by some targets.
This patch keeps that default, but moves the slots behind named offsets so
architecture-specific layouts can describe where the backchain and return
address really live.
On s390x, GCC and Clang do not emit a usable backchain unless -mbackchain is
enabled. Without it, the unwinder stops at the current C frame and the test
reports no Python frames. Once backchains are present, the helper must also
stop at the current thread's known C stack bounds; otherwise it can follow the
final backchain far enough to dereference an invalid frame and segfault.
For Linux s390x backchain frames, the documented z/Architecture stack-frame
layout saves r14, the return-address register, at byte offset 112 from the
frame pointer, so read the return address from that named slot instead of fp[1].
The 112-byte offset comes from Linux's s390 debugging documentation: its Stack
Frame Layout table shows z/Architecture backchain frames with the backchain at
offset 0 and saved r14 of the caller function at offset 112:
https://www.kernel.org/doc/html/v5.3/s390/debugging390.html#stack-frame-layout
This helper remains scoped to Linux s390x backchain frames. GNU SFrame's s390x
notes state that the s390x ELF ABI does not generally mandate where RA and FP
are saved, or whether they are saved at all:
https://sourceware.org/binutils/docs/sframe-spec.html#s390x
As Jens Remus noted, -fno-omit-frame-pointer is not needed when -mbackchain is
present.
On 32-bit ARM, GCC defaults to Thumb mode on common armhf toolchains. The Thumb
prologue keeps the saved frame pointer and link register at offsets that depend
on the generated frame, which breaks the fp[0]/fp[1] walk used by the helper.
Use -marm when it is supported for frame-pointer builds, and teach the helper
the GCC ARM-mode slots where the previous frame pointer is at fp[-1] and the
saved LR return address is at fp[0].
Co-authored-by: Petr Viktorin <encukou@gmail.com>
Co-authored-by: Victor Stinner <vstinner@python.org>
* SEND specialization. Adds 2 new specialized instructions:
* SEND_VIRTUAL: for sends to virtual iterators e.g lists and tuples
* SEND_ASYNC_GEN: for sends to async generators
Tweak FOR_ITER_VIRTUAL so that SEND_VIRTUAL and FOR_ITER_VIRTUAL use equivalent guards
The function__entry and function__return probes stopped working in Python 3.11
when the interpreter was restructured around the new bytecode system. This change
restores these probes by adding DTRACE_FUNCTION_ENTRY() at the start_frame label
in bytecodes.c and DTRACE_FUNCTION_RETURN() in the RETURN_VALUE and YIELD_VALUE
instructions. The helper functions are defined in ceval.c and extract the
filename, function name, and line number from the frame before firing the probe.
This builds on the approach from https://github.com/python/cpython/pull/125019
but avoids modifying the JIT template since the JIT does not currently support
DTrace. The macros are conditionally compiled with WITH_DTRACE and are no-ops
otherwise. The tests have been updated to use modern opcode names (CALL, CALL_KW,
CALL_FUNCTION_EX) and a new bpftrace backend was added for Linux CI alongside
the existing SystemTap tests. Line probe tests were removed since that probe
was never restored after 3.11.
* Add Zd/Zf format support to array, memoryview and struct.
* ctypes: Replace F/D/G complex format with Zf/Zd/Zg.
* Modify array, ctypes and struct modules to support format strings
longer than 1 character (such as "Zd").
* Change array.typecodes type from str to tuple.
The _SSLSocket object now remembers if it gets an EOF error. In this
case, read(), sendfile(), write() and do_handshake method calls fail
with SSLEOFError without calling the underlying OpenSSL function.
Co-authored-by: Gregory P. Smith <greg@krypto.org>
The replaces the incremental GC with a forward port (from 3.13) of the generational GC.
Co-Authored-By: Neil Schemenauer <nas@arctrix.com>
Co-Authored-By: Zanie Blue <contact@zanie.dev>
Co-Authored-By: Sergey Miryanov <sergey.miryanov@gmail.com>
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Add a keyword-only `max_threads` argument to `dump_traceback()` and
`dump_traceback_later()`, defaulting to 100 to preserve existing
behavior. Allows server processes with many worker threads to dump
beyond the historical 100-thread cap (previously a hardcoded
`MAX_NTHREADS = 100` in `Python/traceback.c`).
The cap matters in practice: tstates are prepended to the
PyInterpreterState linked list, so the dump walks newest-first. With
more than 100 threads alive, the main thread (oldest, at the tail) is
silently elided from watchdog dumps -- exactly the thread that's
usually wanted.
The hardcoded value is moved to a new internal macro
`_Py_TRACEBACK_MAX_NTHREADS` in `pycore_traceback.h` so the in-tree
fatal-signal callers all reference one source of truth.
Constant added to Linux 6.16. See the LWN article:
https://lwn.net/Articles/1023085/
Co-authored-by: Brian Schubert <brianm.schubert@gmail.com>
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>
Co-authored-by: Victor Stinner <vstinner@python.org>
Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
Add `canonical=False` keyword argument to `a2b_base64`, `a2b_base32`, `a2b_base85`, and `a2b_ascii85` (and their `base64` module wrappers). When `canonical=True`, non-canonical encodings are rejected per [RFC 4648 section 3.5](https://datatracker.ietf.org/doc/html/rfc4648.html#section-3.5).
This is independent of `strict_mode`.
For base85/ascii85, the check also rejects single-character final groups (never produced by a conforming encoder) and verifies partial group padding matches what the encoder would produce.
Co-authored-by: Serhiy Storchaka via lots of great code review!
* Replaces ad-hoc logic for ending traces with a simple inequality: `fitness < exit_quality`
* Fitness starts high and is reduced for branches, backward edges, calls and trace length
* Exit quality reflect how good a spot that instruction is to end a trace. Closing a loop is very, specializable instructions are very low and the others in between.
The option parsing in Modules/_zstd/decompressor.c had a missing Py_DECREF(value) before the early return -1 when PyLong_AsInt(key) fails. The identical code in Modules/_zstd/compressor.c line 158 has the fix.
