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/Makefile.asm-headers | 105 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 105 insertions(+) create mode 100644 scripts/Makefile.asm-headers (limited to 'scripts/Makefile.asm-headers') diff --git a/scripts/Makefile.asm-headers b/scripts/Makefile.asm-headers new file mode 100644 index 000000000..b38931314 --- /dev/null +++ b/scripts/Makefile.asm-headers @@ -0,0 +1,105 @@ +# SPDX-License-Identifier: GPL-2.0 +# include/asm-generic contains a lot of files that are used +# verbatim by several architectures. +# +# This Makefile generates arch/$(SRCARCH)/include/generated/(uapi/)/asm +# headers from multiple sources: +# - a small wrapper to include the corresponding asm-generic/*.h +# is generated for each file listed as generic-y +# - uapi/asm/unistd_*.h files listed as syscalls-y are generated from +# syscall.tbl with the __NR_* macros +# - Corresponding asm/syscall_table_*.h are generated from the same input + +PHONY := all +all: + +src := $(srctree)/$(subst /generated,,$(obj)) + +syscall_abis_32 += common,32 +syscall_abis_64 += common,64 +syscalltbl := $(srctree)/scripts/syscall.tbl +syshdr-args := --emit-nr + +# let architectures override $(syscall_abis_%) and $(syscalltbl) +-include $(srctree)/arch/$(SRCARCH)/kernel/Makefile.syscalls +include $(srctree)/scripts/Kbuild.include +-include $(kbuild-file) + +syshdr := $(srctree)/scripts/syscallhdr.sh +systbl := $(srctree)/scripts/syscalltbl.sh + +# $(generic)/Kbuild lists mandatory-y. Exclude um since it is a special case. +ifneq ($(SRCARCH),um) +include $(srctree)/$(generic)/Kbuild +endif + +redundant := $(filter $(mandatory-y) $(generated-y), $(generic-y)) +redundant += $(foreach f, $(generic-y), $(if $(wildcard $(src)/$(f)),$(f))) +redundant := $(sort $(redundant)) +$(if $(redundant),\ + $(warning redundant generic-y found in $(src)/Kbuild: $(redundant))) + +# If arch does not implement mandatory headers, fallback to asm-generic ones. +mandatory-y := $(filter-out $(generated-y), $(mandatory-y)) +generic-y += $(foreach f, $(mandatory-y), $(if $(wildcard $(src)/$(f)),,$(f))) + +generic-y := $(addprefix $(obj)/, $(generic-y)) +syscall-y := $(addprefix $(obj)/, $(syscall-y)) +generated-y := $(addprefix $(obj)/, $(generated-y)) + +# Remove stale wrappers when the corresponding files are removed from generic-y +old-headers := $(shell test -d $(obj) && find $(obj) -name *.h) +unwanted := $(filter-out $(generic-y) $(generated-y) $(syscall-y),$(old-headers)) + +filechk_wrap = echo "\#include " + +quiet_cmd_remove = REMOVE $(unwanted) + cmd_remove = rm -f $(unwanted); find $(obj) -type d -empty -delete + +quiet_cmd_syshdr = SYSHDR $@ + cmd_syshdr = $(CONFIG_SHELL) $(syshdr) \ + $(if $(syshdr-args-$*),$(syshdr-args-$*),$(syshdr-args)) \ + $(if $(syscall_compat),--prefix "compat$*_") \ + --abis $(subst $(space),$(comma),$(strip $(syscall_abis_$*))) \ + $< $@ + +quiet_cmd_systbl = SYSTBL $@ + cmd_systbl = $(CONFIG_SHELL) $(systbl) \ + $(if $(systbl-args-$*),$(systbl-args-$*),$(systbl-args)) \ + --abis $(subst $(space),$(comma),$(strip $(syscall_abis_$*))) \ + $< $@ + +all: $(generic-y) $(syscall-y) + $(if $(unwanted),$(call cmd,remove)) + @: + +$(obj)/%.h: $(srctree)/$(generic)/%.h FORCE + $(call filechk,wrap) + +$(obj)/unistd_%.h: $(syscalltbl) $(syshdr) FORCE + $(call if_changed,syshdr) + +$(obj)/unistd_compat_%.h: syscall_compat:=1 +$(obj)/unistd_compat_%.h: $(syscalltbl) $(syshdr) FORCE + $(call if_changed,syshdr) + +$(obj)/syscall_table_%.h: $(syscalltbl) $(systbl) FORCE + $(call if_changed,systbl) + +targets := $(syscall-y) + +# Create output directory. Skip it if at least one old header exists +# since we know the output directory already exists. +ifeq ($(old-headers),) +$(shell mkdir -p $(obj)) +endif + +PHONY += FORCE + +FORCE: + +existing-targets := $(wildcard $(sort $(targets))) + +-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd) + +.PHONY: $(PHONY) -- cgit v1.3.1