From 4310c6b8e75d6a47f7548e5948fbe6318aa4440a Mon Sep 17 00:00:00 2001 From: Fedor Pchelkin Date: Mon, 31 Aug 2026 10:58:09 +0300 Subject: thunderbolt: Fix NULL dereference in tb_remove_work() There is a slight race between tb_remove_work() and tb_domain_remove() which leads to dereferencing a NULL tb->root_switch pointer inside tb_free_unplugged_xdomains(): Thread A Thread B tb_remove_work() tb_domain_remove() mutex_lock(&tb->lock) tb_stop() /* doesn't cancel a running callback */ cancel_delayed_work(&tcm->remove_work) ... tb_switch_remove(tb->root_switch) tb->root_switch = NULL mutex_unlock(&tb->lock) mutex_lock(&tb->lock) ... /* without checking ->root_switch */ tb_free_unplugged_xdomains(tb->root_switch) mutex_unlock(&tb->lock) Commit a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without holding tb->lock") doesn't seem right to move tb_free_unplugged_xdomains() out of the &tb->lock section and the check for tb->root_switch, in particular. It states: For this reason separate removing the XDomain from the topology data structures (where we need the lock) from unregistering the device from the bus (where remove callbacks of the drivers are being called). tb_free_unplugged_xdomains() belongs to the former group of functions requiring the lock. And it also calls tb_xdomain_remove() which should only be called with &tb->lock held. Found by Linux Verification Center (linuxtesting.org) with Svace static analysis tool. Fixes: a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without holding tb->lock") Cc: stable@vger.kernel.org Signed-off-by: Fedor Pchelkin Signed-off-by: Mika Westerberg --- Documentation/sphinx/kernel_feat.py | 137 ++++++++++++++++++++++++++++++++++++ 1 file changed, 137 insertions(+) create mode 100644 Documentation/sphinx/kernel_feat.py (limited to 'Documentation/sphinx/kernel_feat.py') diff --git a/Documentation/sphinx/kernel_feat.py b/Documentation/sphinx/kernel_feat.py new file mode 100644 index 000000000..bdc0fef5c --- /dev/null +++ b/Documentation/sphinx/kernel_feat.py @@ -0,0 +1,137 @@ +# coding=utf-8 +# SPDX-License-Identifier: GPL-2.0 +# +""" + kernel-feat + ~~~~~~~~~~~ + + Implementation of the ``kernel-feat`` reST-directive. + + :copyright: Copyright (C) 2016 Markus Heiser + :copyright: Copyright (C) 2016-2019 Mauro Carvalho Chehab + :maintained-by: Mauro Carvalho Chehab + :license: GPL Version 2, June 1991 see Linux/COPYING for details. + + The ``kernel-feat`` (:py:class:`KernelFeat`) directive calls the + tools/docs/get_feat.pl script to parse the Kernel ABI files. + + Overview of directive's argument and options. + + .. code-block:: rst + + .. kernel-feat:: + :debug: + + The argument ```` is required. It contains the + location of the ABI files to be parsed. + + ``debug`` + Inserts a code-block with the *raw* reST. Sometimes it is helpful to see + what reST is generated. + +""" + +import codecs +import os +import re +import sys + +from docutils import nodes, statemachine +from docutils.statemachine import ViewList +from docutils.parsers.rst import directives, Directive +from sphinx.util.docutils import switch_source_input + +srctree = os.path.abspath(os.environ["srctree"]) +sys.path.insert(0, os.path.join(srctree, "tools/lib/python")) + +from feat.parse_features import ParseFeature # pylint: disable=C0413 + +def ErrorString(exc): # Shamelessly stolen from docutils + return f'{exc.__class__.__name}: {exc}' + +__version__ = '1.0' + +def setup(app): + + app.add_directive("kernel-feat", KernelFeat) + return dict( + version = __version__ + , parallel_read_safe = True + , parallel_write_safe = True + ) + +class KernelFeat(Directive): + + """KernelFeat (``kernel-feat``) directive""" + + required_arguments = 1 + optional_arguments = 2 + has_content = False + final_argument_whitespace = True + + option_spec = { + "debug" : directives.flag + } + + def warn(self, message, **replace): + replace["fname"] = self.state.document.current_source + replace["line_no"] = replace.get("line_no", self.lineno) + message = ("%(fname)s:%(line_no)s: [kernel-feat WARN] : " + message) % replace + self.state.document.settings.env.app.warn(message, prefix="") + + def run(self): + doc = self.state.document + if not doc.settings.file_insertion_enabled: + raise self.warning("docutils: file insertion disabled") + + env = doc.settings.env + + srctree = os.path.abspath(os.environ["srctree"]) + + feature_dir = os.path.join(srctree, 'Documentation', self.arguments[0]) + + feat = ParseFeature(feature_dir, False, True) + feat.parse() + + if len(self.arguments) > 1: + arch = self.arguments[1] + lines = feat.output_arch_table(arch) + else: + lines = feat.output_matrix() + + line_regex = re.compile(r"^\.\. FILE (\S+)$") + + out_lines = "" + + for line in lines.split("\n"): + match = line_regex.search(line) + if match: + fname = match.group(1) + + # Add the file to Sphinx build dependencies + env.note_dependency(os.path.abspath(fname)) + else: + out_lines += line + "\n" + + nodeList = self.nestedParse(out_lines, self.arguments[0]) + return nodeList + + def nestedParse(self, lines, fname): + content = ViewList() + node = nodes.section() + + if "debug" in self.options: + code_block = "\n\n.. code-block:: rst\n :linenos:\n" + for l in lines.split("\n"): + code_block += "\n " + l + lines = code_block + "\n\n" + + for c, l in enumerate(lines.split("\n")): + content.append(l, fname, c) + + buf = self.state.memo.title_styles, self.state.memo.section_level, self.state.memo.reporter + + with switch_source_input(self.state, content): + self.state.nested_parse(content, 0, node, match_titles=1) + + return node.children -- cgit v1.3.1