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/misc-check | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100755 scripts/misc-check (limited to 'scripts/misc-check') diff --git a/scripts/misc-check b/scripts/misc-check new file mode 100755 index 000000000..40e5a4b01 --- /dev/null +++ b/scripts/misc-check @@ -0,0 +1,76 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only + +set -e + +# Detect files that are tracked but ignored by git. +check_tracked_ignored_files () { + git -C "${srctree:-.}" ls-files -i -c --exclude-per-directory=.gitignore 2>/dev/null | + sed 's/$/: warning: ignored by one of the .gitignore files/' >&2 +} + +# Check for missing #include +# +# The rule for including is very simple: +# Include only when you use EXPORT_SYMBOL(). That's it. +# +# However, some headers include even though they are completely +# unrelated to EXPORT_SYMBOL(). +# +# One example is include/linux/module.h. Please note and +# are orthogonal. should be included by files +# that can be compiled as modules. In other words, should be +# included by EXPORT_SYMBOL consumers. In contrast, should be +# included from EXPORT_SYMBOL providers, which may or may not be modular. +# Hence, include/linux/module.h should *not* include . +# +# Another example is include/linux/linkage.h, which is completely unrelated to +# EXPORT_SYMBOL(). Worse, it is included by most C files, which means, most C +# files end up including , even though only some of them +# actually export symbols. Hence, include/linux/linkage.h should *not* include +# . +# +# Before fixing such headers, we must ensure that C files using EXPORT_SYMBOL() +# include directly, since many C files currently rely on +# being included indirectly (likely, via etc.). +# +# Therefore, this check. +# +# The problem is simple - the warned files use EXPORT_SYMBOL(), but do not +# include . Please add #include to them. +# +# If the included headers are sorted alphabetically, please insert +# in the appropriate position to maintain the sort order. +# For this reason, this script only checks missing , but +# does not automatically fix it. +check_missing_include_linux_export_h () { + + git -C "${srctree:-.}" grep --files-with-matches -E 'EXPORT_SYMBOL((_NS)?(_GPL)?|_FOR_MODULES)\(.*\)' \ + -- '*.[ch]' :^tools/ :^include/linux/export.h | + xargs -r git -C "${srctree:-.}" grep --files-without-match '#include[[:space:]]*' | + xargs -r printf "%s: warning: EXPORT_SYMBOL() is used, but #include is missing\n" >&2 +} + +# If you do not use EXPORT_SYMBOL(), please do not include . +# Currently, this is checked for *.c files, but not for *.h files, because some +# *.c files rely on being included indirectly. +check_unnecessary_include_linux_export_h () { + + git -C "${srctree:-.}" grep --files-with-matches '#include[[:space:]]*' \ + -- '*.[c]' :^tools/ | + xargs -r git -C "${srctree:-.}" grep --files-without-match -E 'EXPORT_SYMBOL((_NS)?(_GPL)?|_FOR_MODULES)\(.*\)' | + xargs -r printf "%s: warning: EXPORT_SYMBOL() is not used, but #include is present\n" >&2 +} + +case "${KBUILD_EXTRA_WARN}" in +*1*) + check_tracked_ignored_files + ;; +esac + +case "${KBUILD_EXTRA_WARN}" in +*2*) + check_missing_include_linux_export_h + check_unnecessary_include_linux_export_h + ;; +esac -- cgit v1.3.1