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 --- scripts/check-sysctl-docs | 174 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 174 insertions(+) create mode 100755 scripts/check-sysctl-docs (limited to 'scripts/check-sysctl-docs') diff --git a/scripts/check-sysctl-docs b/scripts/check-sysctl-docs new file mode 100755 index 000000000..910fd8a9a --- /dev/null +++ b/scripts/check-sysctl-docs @@ -0,0 +1,174 @@ +#!/usr/bin/env -S gawk -f +# SPDX-License-Identifier: GPL-2.0 + +# Script to check sysctl documentation against source files +# +# Copyright (c) 2020 Stephen Kitt + +# Example invocation: +# scripts/check-sysctl-docs -vtable="kernel" \ +# Documentation/admin-guide/sysctl/kernel.rst \ +# $(git grep -l register_sysctl) +# +# Specify -vdebug=1 to see debugging information + +BEGIN { + if (!table) { + print "Please specify the table to look for using the table variable" > "/dev/stderr" + exit 1 + } + + # Documentation title skiplist + skiplist[0] = "^Documentation for" + skiplist[1] = "Network core options$" + skiplist[2] = "POSIX message queues filesystem$" + skiplist[3] = "Configuration options" + skiplist[4] = ". /proc/sys/fs" + skiplist[5] = "^Introduction$" + skiplist[6] = "^seccomp$" + skiplist[7] = "^pty$" + skiplist[8] = "^firmware_config$" + skiplist[9] = "^random$" +} + +# The following globals are used: +# documented: maps documented entries (each key is an entry) +# entries: maps ctl_table names and procnames to counts (so +# enumerating the subkeys for a given ctl_table lists its +# procnames) +# curtable: the name of the current ctl_table struct +# curentry: the name of the current proc entry (procname when parsing +# a ctl_table, constructed path when parsing a ctl_path) + + +# Remove punctuation from the given value +function trimpunct(value) { + while (value ~ /^["&]/) { + value = substr(value, 2) + } + while (value ~ /[]["&,}]$/) { + value = substr(value, 1, length(value) - 1) + } + return value +} + +# Print the information for the given entry +function printentry(entry) { + seen[entry]++ + printf "* %s from %s", entry, file[entry] + if (documented[entry]) { + printf " (documented)" + } + print "" +} + + +# Stage 1: build the list of documented entries +FNR == NR && /^=+$/ { + for (i in skiplist) { + if (prevline ~ skiplist[i]) { + next + } + } + + # The previous line is a section title, parse it + $0 = prevline + if (debug) print "Parsing " $0 + inbrackets = 0 + for (i = 1; i <= NF; i++) { + if (length($i) == 0) { + continue + } + if (!inbrackets && substr($i, 1, 1) == "(") { + inbrackets = 1 + } + if (!inbrackets) { + token = trimpunct($i) + if (length(token) > 0 && token != "and") { + if (debug) print trimpunct($i) + documented[trimpunct($i)]++ + } + } + if (inbrackets && substr($i, length($i), 1) == ")") { + inbrackets = 0 + } + } +} + +FNR == NR { + prevline = $0 + next +} + + +# Stage 2: process each file and find all sysctl tables +BEGINFILE { + delete entries + curtable = "" + curentry = "" + delete vars + if (debug) print "Processing file " FILENAME +} + +/^static( const)? struct ctl_table/ { + match($0, /static( const)? struct ctl_table ([^][]+)/, tables) + curtable = tables[2] + if (debug) print "Processing table " curtable +} + +/^};$/ { + curtable = "" + curentry = "" + delete vars +} + +curtable && /\.procname[\t ]*=[\t ]*".+"/ { + match($0, /.procname[\t ]*=[\t ]*"([^"]+)"/, names) + curentry = names[1] + if (debug) print "Adding entry " curentry " to table " curtable + entries[curtable][curentry]++ + file[curentry] = FILENAME +} + +curtable && /UCOUNT_ENTRY.*/ { + match($0, /UCOUNT_ENTRY\("([^"]+)"\)/, names) + curentry = names[1] + if (debug) print "Adding entry " curentry " to table " curtable + entries[curtable][curentry]++ + file[curentry] = FILENAME +} + +/register_sysctl.*/ { + match($0, /register_sysctl(|_init|_sz)\("([^"]+)" *, *([^,)]+)/, tables) + if (debug) print "Registering table " tables[3] " at " tables[2] + if (tables[2] == table) { + for (entry in entries[tables[3]]) { + printentry(entry) + } + } +} + +/kmemdup.*/ { + match($0, /([^ \t]+) *= *kmemdup\(([^,]+) *,/, names) + if (debug) print "Found variable " names[1] " for table " names[2] + if (names[2] in entries) { + vars[names[1]] = names[2] + } +} + +/__register_sysctl_table.*/ { + match($0, /__register_sysctl_table\([^,]+, *"([^"]+)" *, *([^,]+)/, tables) + if (debug) print "Registering variable table " tables[2] " at " tables[1] + if (tables[1] == table && tables[2] in vars) { + for (entry in entries[vars[tables[2]]]) { + printentry(entry) + } + } +} + +END { + for (entry in documented) { + if (!seen[entry]) + print "No implementation for " entry + } +} -- cgit v1.3.1