ftrace: Synchronize the initialization of ftrace_opsgrafted

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 <rostedt@goodmis.org>

1 files changed, 199 insertions, 0 deletions

diff --git a/scripts/container b/scripts/container
new file mode 100755
index 000000000..b05333d85
--- /dev/null
+++ b/scripts/container
@@ -0,0 +1,199 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only
+# Copyright (C) 2025 Guillaume Tucker
+
+"""Containerized builds"""
+
+import abc
+import argparse
+import logging
+import os
+import pathlib
+import shutil
+import subprocess
+import sys
+import uuid
+
+
+class ContainerRuntime(abc.ABC):
+    """Base class for a container runtime implementation"""
+
+    name = None  # Property defined in each implementation class
+
+    def __init__(self, args, logger):
+        self._uid = args.uid or os.getuid()
+        self._gid = args.gid or args.uid or os.getgid()
+        self._env_file = args.env_file
+        self._shell = args.shell
+        self._logger = logger
+
+    @classmethod
+    def is_present(cls):
+        """Determine whether the runtime is present on the system"""
+        return shutil.which(cls.name) is not None
+
+    @abc.abstractmethod
+    def _do_run(self, image, cmd, container_name):
+        """Runtime-specific handler to run a command in a container"""
+
+    @abc.abstractmethod
+    def _do_abort(self, container_name):
+        """Runtime-specific handler to abort a running container"""
+
+    def run(self, image, cmd):
+        """Run a command in a runtime container"""
+        container_name = str(uuid.uuid4())
+        self._logger.debug("container: %s", container_name)
+        try:
+            return self._do_run(image, cmd, container_name)
+        except KeyboardInterrupt:
+            self._logger.error("user aborted")
+            self._do_abort(container_name)
+            return 1
+
+
+class CommonRuntime(ContainerRuntime):
+    """Common logic for Docker and Podman"""
+
+    def _do_run(self, image, cmd, container_name):
+        cmdline = [self.name, 'run']
+        cmdline += self._get_opts(container_name)
+        cmdline.append(image)
+        cmdline += cmd
+        self._logger.debug('command: %s', ' '.join(cmdline))
+        return subprocess.call(cmdline)
+
+    def _get_opts(self, container_name):
+        opts = [
+            '--name', container_name,
+            '--rm',
+            '--volume', f'{pathlib.Path.cwd()}:/src',
+            '--workdir', '/src',
+        ]
+        if self._env_file:
+            opts += ['--env-file', self._env_file]
+        if self._shell:
+            opts += ['--interactive', '--tty']
+        return opts
+
+    def _do_abort(self, container_name):
+        subprocess.call([self.name, 'kill', container_name])
+
+
+class DockerRuntime(CommonRuntime):
+    """Run a command in a Docker container"""
+
+    name = 'docker'
+
+    def _get_opts(self, container_name):
+        return super()._get_opts(container_name) + [
+            '--user', f'{self._uid}:{self._gid}'
+        ]
+
+
+class PodmanRuntime(CommonRuntime):
+    """Run a command in a Podman container"""
+
+    name = 'podman'
+
+    def _get_opts(self, container_name):
+        return super()._get_opts(container_name) + [
+            '--userns', f'keep-id:uid={self._uid},gid={self._gid}',
+        ]
+
+
+class Runtimes:
+    """List of all supported runtimes"""
+
+    runtimes = [PodmanRuntime, DockerRuntime]
+
+    @classmethod
+    def get_names(cls):
+        """Get a list of all the runtime names"""
+        return list(runtime.name for runtime in cls.runtimes)
+
+    @classmethod
+    def get(cls, name):
+        """Get a single runtime class matching the given name"""
+        for runtime in cls.runtimes:
+            if runtime.name == name:
+                if not runtime.is_present():
+                    raise ValueError(f"runtime not found: {name}")
+                return runtime
+        raise ValueError(f"unknown runtime: {name}")
+
+    @classmethod
+    def find(cls):
+        """Find the first runtime present on the system"""
+        for runtime in cls.runtimes:
+            if runtime.is_present():
+                return runtime
+        raise ValueError("no runtime found")
+
+
+def _get_logger(verbose):
+    """Set up a logger with the appropriate level"""
+    logger = logging.getLogger('container')
+    handler = logging.StreamHandler()
+    handler.setFormatter(logging.Formatter(
+        fmt='[container {levelname}] {message}', style='{'
+    ))
+    logger.addHandler(handler)
+    logger.setLevel(logging.DEBUG if verbose is True else logging.INFO)
+    return logger
+
+
+def main(args):
+    """Main entry point for the container tool"""
+    logger = _get_logger(args.verbose)
+    try:
+        cls = Runtimes.get(args.runtime) if args.runtime else Runtimes.find()
+    except ValueError as ex:
+        logger.error(ex)
+        return 1
+    logger.debug("runtime: %s", cls.name)
+    logger.debug("image: %s", args.image)
+    return cls(args, logger).run(args.image, args.cmd)
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(
+        'container',
+        description="See the documentation for more details: "
+        "https://docs.kernel.org/dev-tools/container.html"
+    )
+    parser.add_argument(
+        '-e', '--env-file',
+        help="Path to an environment file to load in the container."
+    )
+    parser.add_argument(
+        '-g', '--gid',
+        help="Group ID to use inside the container."
+    )
+    parser.add_argument(
+        '-i', '--image', required=True,
+        help="Container image name."
+    )
+    parser.add_argument(
+        '-r', '--runtime', choices=Runtimes.get_names(),
+        help="Container runtime name.  If not specified, the first one found "
+        "on the system will be used i.e. Podman if present, otherwise Docker."
+    )
+    parser.add_argument(
+        '-s', '--shell', action='store_true',
+        help="Run the container in an interactive shell."
+    )
+    parser.add_argument(
+        '-u', '--uid',
+        help="User ID to use inside the container.  If the -g option is not "
+        "specified, the user ID will also be set as the group ID."
+    )
+    parser.add_argument(
+        '-v', '--verbose', action='store_true',
+        help="Enable verbose output."
+    )
+    parser.add_argument(
+        'cmd', nargs='+',
+        help="Command to run in the container"
+    )
+    sys.exit(main(parser.parse_args(sys.argv[1:])))