From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- tools/perf/util/setup.py | 194 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 194 insertions(+) create mode 100644 tools/perf/util/setup.py (limited to 'tools/perf/util/setup.py') diff --git a/tools/perf/util/setup.py b/tools/perf/util/setup.py new file mode 100644 index 000000000..8380980ad --- /dev/null +++ b/tools/perf/util/setup.py @@ -0,0 +1,194 @@ +# SPDX-License-Identifier: GPL-2.0 +"""Setup script for perf python extension. + +This script is used to build and install the perf python binding. +It handles compiler-specific flags, especially for clang, and configures +the setuptools Extension. +""" + +import os +import shlex +import shutil +import subprocess +import sysconfig + +from setuptools import setup, Extension +from setuptools.command.build_ext import build_ext as _build_ext +from setuptools.command.install_lib import install_lib as _install_lib + + +def clang_has_option(cc: str, cc_args: list[str], src_feature_tests: str, option: str) -> bool: + """Check if clang supports a specific option. + + Args: + cc: The compiler executable. + cc_args: Compiler arguments from CC environment variable. + src_feature_tests: Path to the feature tests directory. + option: The compiler option to check (e.g., "-mcet"). + + Returns: + True if the option is supported, False otherwise. + """ + error_substrings = ( + b"unknown argument", + b"is not supported", + b"unknown warning option" + ) + cmd = [cc] + cc_args + [ + option, + "-o", "/dev/null", + os.path.join(src_feature_tests, "test-hello.c") + ] + try: + res = subprocess.run(cmd, stderr=subprocess.PIPE, stdout=subprocess.DEVNULL, check=False) + cc_output = res.stderr.splitlines() + except OSError: + return False + return not any(any(error in line for error in error_substrings) for line in cc_output) + + +def filter_clang_options(cc: str, cc_args: list[str], src_feature_tests: str) -> None: + """Filter out unsupported clang options from sysconfig CFLAGS and OPT. + + Args: + cc: The compiler executable. + cc_args: Compiler arguments from CC environment variable. + src_feature_tests: Path to the feature tests directory. + """ + config_vars = sysconfig.get_config_vars() + for var in ('CFLAGS', 'OPT'): + if var not in config_vars: + continue + + # Split into individual flags using shlex to preserve quoted arguments + flags = shlex.split(config_vars[var]) + + # Remove -specs=... + flags = [f for f in flags if not f.startswith("-specs=")] + + options = ( + "-mcet", + "-fcf-protection", + "-fstack-clash-protection", + "-fstack-protector-strong", + "-fno-semantic-interposition", + "-ffat-lto-objects", + "-ftree-loop-distribute-patterns", + "-gno-variable-location-views" + ) + for option in options: + if not clang_has_option(cc, cc_args, src_feature_tests, option): + # Remove the option and any variant (e.g. -option=...) + flags = [f for f in flags if not f.startswith(option)] + + # Re-join flags preserving quoting + config_vars[var] = shlex.join(flags) + + +class BuildExt(_build_ext): + """Custom build_ext command to set output directories.""" + + def __init__(self, *args, **kwargs): + self.build_lib = None + self.build_temp = None + super().__init__(*args, **kwargs) + + def finalize_options(self) -> None: + _build_ext.finalize_options(self) + build_lib = os.getenv('PYTHON_EXTBUILD_LIB') + build_tmp = os.getenv('PYTHON_EXTBUILD_TMP') + if build_lib: + self.build_lib = build_lib + if build_tmp: + self.build_temp = build_tmp + + +class InstallLib(_install_lib): + """Custom install_lib command to set output directory.""" + + def __init__(self, *args, **kwargs): + self.build_dir = None + super().__init__(*args, **kwargs) + + def finalize_options(self) -> None: + _install_lib.finalize_options(self) + build_lib = os.getenv('PYTHON_EXTBUILD_LIB') + if build_lib: + self.build_dir = build_lib + + def run(self): + _install_lib.run(self) + srctree = os.getenv('srctree', '.') + src_perf = os.path.join(srctree, 'tools/perf') + shutil.copy2(os.path.join(src_perf, 'python/perf.pyi'), self.install_dir) + + +def main() -> None: + """Main entry point for the setup script.""" + cc_env = os.getenv("CC") + assert cc_env, "Environment variable CC not set" + + # Safe parsing of CC environment variable which might contain options/quotes + cc_tokens = shlex.split(cc_env) + cc = cc_tokens[0] + cc_args = cc_tokens[1:] + + # Run CC -v to check if it is clang. + try: + cc_info = subprocess.run( + [cc, "-v"], stderr=subprocess.PIPE, stdout=subprocess.DEVNULL, check=False + ) + cc_is_clang = b"clang version" in cc_info.stderr + except OSError as e: + raise RuntimeError(f"Failed to execute compiler '{cc}': {e}") from e + + srctree = os.getenv('srctree') + assert srctree, "Environment variable srctree, for the Linux sources, not set" + src_feature_tests = f'{srctree}/tools/build/feature' + + if cc_is_clang: + filter_clang_options(cc, cc_args, src_feature_tests) + + # switch off several checks (need to be at the end of cflags list) + cflags = [ + '-fno-strict-aliasing', + '-Wno-write-strings', + '-Wno-unused-parameter', + '-Wno-redundant-decls' + ] + if cc_is_clang: + cflags += ["-Wno-unused-command-line-argument"] + if clang_has_option( + cc, cc_args, src_feature_tests, "-Wno-cast-function-type-mismatch" + ): + cflags += ["-Wno-cast-function-type-mismatch"] + else: + cflags += ['-Wno-cast-function-type'] + + # The python headers have mixed code with declarations (decls after asserts, for instance) + cflags += ["-Wno-declaration-after-statement"] + + src_perf = f'{srctree}/tools/perf' + + perf = Extension( + 'perf', + sources=[os.path.join(src_perf, 'util/python.c')], + include_dirs=['util/include'], + extra_compile_args=cflags, + ) + + setup( + name='perf', + version='0.1', + description='Interface with the Linux profiling infrastructure', + author='Arnaldo Carvalho de Melo', + author_email='acme@redhat.com', + license='GPLv2', + url='http://perf.wiki.kernel.org', + ext_modules=[perf], + cmdclass={'build_ext': BuildExt, 'install_lib': InstallLib}, + ) + + +if __name__ == '__main__': + main() -- cgit v1.3.1