Subject: 30.0.50; Calling (profiler-cpu-log) segfaults Emacs if profiler is not running

From: Aaron Zeng <[email-masked]>
Date: Wed, 11 Jun 2025 17:03:04 -0400

As of commit 22201dde773e5404f80baa1f59768e88d97a322a, calling
(profiler-cpu-log) while the CPU profiler is not running causes Emacs to
crash with a segfault.  I have confirmed this issue also appears at
f69b822fb0e804a13ff7a4eb55fc2ae618e0de72, which was the tip of the
master branch at the time of writing.

To reproduce, simply run:
$ emacs -Q --batch --eval '(profiler-cpu-log)'

The gdb backtrace is attached to this email.

In GNU Emacs 30.0.50 (build 7, x86_64-pc-linux-gnu, X toolkit, cairo
 version 1.15.12, Xaw scroll bars) of 2025-06-11 built on
 igm-qws-u12685a
Repository revision: 22201dde773e5404f80baa1f59768e88d97a322a
Repository branch: HEAD
System Description: Rocky Linux 8.10 (Green Obsidian)

Configured using:
 'configure --config-cache --with-x-toolkit=lucid --without-gpm
 --without-gconf --without-selinux --without-imagemagick --with-modules
 --with-gif=no --with-cairo --with-rsvg --without-compress-install
 --with-tree-sitter --with-native-compilation=aot --prefix=
 'CFLAGS=-ggdb3 -Og -fno-omit-frame-pointer' LDFLAGS=-ggdb3'

Configured features:
CAIRO DBUS FREETYPE GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON
LIBSYSTEMD LIBXML2 MODULES NATIVE_COMP NOTIFY INOTIFY PDUMPER PNG RSVG
SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS TREE_SITTER X11
XDBE XIM XINPUT2 XPM LUCID ZLIB

Important settings:
  value of $LANG: en_US.utf8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  minibuffer-regexp-mode: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
epg-config gnus-util time-date subr-x mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader cl-loaddefs cl-lib
sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils
compile text-property-search comint ansi-osc ansi-color ring comp-run
comp-common rx term/xterm xterm byte-opt gv bytecomp byte-compile rmc
iso-transl tooltip cconv eldoc paren electric uniquify ediff-hook
vc-hooks lisp-float-type elisp-mode mwheel term/x-win x-win
term/common-win x-dnd touch-screen tool-bar dnd fontset image regexp-opt
fringe tabulated-list replace newcomment text-mode lisp-mode prog-mode
register page tab-bar menu-bar rfn-eshadow isearch easymenu timer select
scroll-bar mouse jit-lock font-lock syntax font-core term/tty-colors
frame minibuffer nadvice seq simple cl-generic indonesian philippine
cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech
european ethiopic indian cyrillic chinese composite emoji-zwj charscript
charprop case-table epa-hook jka-cmpr-hook help abbrev obarray oclosure
cl-preloaded button loaddefs theme-loaddefs faces cus-face macroexp
files window text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget keymap hashtable-print-readable backquote
threads dbusbind inotify dynamic-setting system-font-setting
font-render-setting cairo x-toolkit xinput2 x multi-tty move-toolbar
make-network-process native-compile emacs)

Memory information:
((conses 16 108023 11051) (symbols 48 6804 0) (strings 32 28851 2118)
 (string-bytes 1 959502) (vectors 16 17388)
 (vector-slots 8 258214 11288) (floats 8 38 51) (intervals 56 297 3)
 (buffers 984 11))