From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops 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 --- tools/build/Makefile.feature | 334 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 334 insertions(+) create mode 100644 tools/build/Makefile.feature (limited to 'tools/build/Makefile.feature') diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature new file mode 100644 index 000000000..99eb0ea09 --- /dev/null +++ b/tools/build/Makefile.feature @@ -0,0 +1,334 @@ +# SPDX-License-Identifier: GPL-2.0-only +feature_dir := $(srctree)/tools/build/feature + +ifneq ($(OUTPUT),) + OUTPUT_FEATURES = $(OUTPUT)feature/ + $(shell mkdir -p $(OUTPUT_FEATURES)) +endif + +feature_check = $(eval $(feature_check_code)) +define feature_check_code + feature-$(1) := $(shell $(MAKE) OUTPUT=$(OUTPUT_FEATURES) CC="$(CC)" CXX="$(CXX)" CFLAGS="$(EXTRA_CFLAGS) $(FEATURE_CHECK_CFLAGS-$(1))" CXXFLAGS="$(EXTRA_CXXFLAGS) $(FEATURE_CHECK_CXXFLAGS-$(1))" LDFLAGS="$(LDFLAGS) $(FEATURE_CHECK_LDFLAGS-$(1))" -C $(feature_dir) $(OUTPUT_FEATURES)test-$1.bin >/dev/null 2>/dev/null && echo 1 || echo 0) +endef + +feature_set = $(eval $(feature_set_code)) +define feature_set_code + feature-$(1) := 1 +endef + +# +# Build the feature check binaries in parallel, ignore errors, ignore return value and suppress output: +# + +# +# Note that this is not a complete list of all feature tests, just +# those that are typically built on a fully configured system. +# +# [ Feature tests not mentioned here have to be built explicitly in +# the rule that uses them - an example for that is the 'bionic' +# feature check. ] +# +# These + the ones in FEATURE_TESTS_EXTRA are included in +# tools/build/feature/test-all.c and we try to build it all together +# then setting all those features to '1' meaning they are all enabled. +# +# There are things like fortify-source that will be set to 1 because test-all +# is built with the flags needed to test if its enabled, resulting in +# +# $ rm -rf /tmp/b ; mkdir /tmp/b ; make -C tools/perf O=/tmp/b feature-dump +# $ grep fortify-source /tmp/b/FEATURE-DUMP +# feature-fortify-source=1 +# $ +# +# All the others should have lines in tools/build/feature/test-all.c like: +# +# #define main main_test_disassembler_init_styled +# # include "test-disassembler-init-styled.c" +# #undef main +# +# #define main main_test_libzstd +# # include "test-libzstd.c" +# #undef main +# +# int main(int argc, char *argv[]) +# { +# main_test_disassembler_four_args(); +# main_test_libzstd(); +# return 0; +# } +# +# If the sample above works, then we end up with these lines in the FEATURE-DUMP +# file: +# +# feature-disassembler-four-args=1 +# feature-libzstd=1 +# +FEATURE_TESTS_BASIC := \ + backtrace \ + libdw \ + eventfd \ + fortify-source \ + gettid \ + glibc \ + libbfd \ + libbfd-threadsafe \ + libelf \ + libelf-getphdrnum \ + libelf-gelf_getnote \ + libelf-getshdrstrndx \ + libelf-zstd \ + libnuma \ + numa_num_possible_cpus \ + libpython \ + libslang \ + libtraceevent \ + libcpupower \ + pthread-attr-setaffinity-np \ + pthread-barrier \ + reallocarray \ + stackprotector-all \ + timerfd \ + zlib \ + lzma \ + bpf \ + scandirat \ + sched_getcpu \ + sdt \ + setns \ + libaio \ + libzstd \ + disassembler-four-args \ + disassembler-init-styled \ + file-handle \ + libopenssl + +# FEATURE_TESTS_BASIC + FEATURE_TESTS_EXTRA is the complete list +# of all feature tests + +LIBUNWIND_ARCHS:=aarch64 arm loongarch64 mips ppc32 ppc64 riscv s390x x86 x86_64 + +FEATURE_TESTS_EXTRA := \ + bionic \ + compile-32 \ + compile-x32 \ + cplus-demangle \ + cxa-demangle \ + gtk2 \ + gtk2-infobar \ + hello \ + babeltrace2-ctf-writer \ + libcapstone \ + libcheck \ + libbfd-liberty \ + libbfd-liberty-z \ + libopencsd \ + libperl \ + llvm \ + libbpf \ + libpfm4 \ + libdebuginfod \ + clang-bpf-co-re \ + bpftool-skeletons \ + libunwind \ + libunwind-debug-frame \ + $(foreach arch,$(LIBUNWIND_ARCHS),libunwind-$(arch) libunwind-debug-frame-$(arch)) + + +FEATURE_TESTS ?= $(FEATURE_TESTS_BASIC) + +ifeq ($(FEATURE_TESTS),all) + FEATURE_TESTS := $(FEATURE_TESTS_BASIC) $(FEATURE_TESTS_EXTRA) +endif + +FEATURE_DISPLAY ?= \ + libdw \ + glibc \ + libelf \ + libnuma \ + numa_num_possible_cpus \ + libpython \ + libcapstone \ + llvm-perf \ + zlib \ + lzma \ + bpf \ + libaio \ + libzstd \ + libopenssl \ + rust + +# +# Declare group members of a feature to display the logical OR of the detection +# result instead of each member result. +# +FEATURE_GROUP_MEMBERS-libbfd = libbfd-liberty libbfd-liberty-z + +# +# Declare list of feature dependency packages that provide pkg-config files. +# +FEATURE_PKG_CONFIG ?= \ + babeltrace2-ctf-writer \ + libtraceevent \ + libtracefs + +feature_pkg_config = $(eval $(feature_pkg_config_code)) +define feature_pkg_config_code + FEATURE_CHECK_CFLAGS-$(1) := $(shell $(PKG_CONFIG) --cflags $(1) 2>/dev/null) + FEATURE_CHECK_LDFLAGS-$(1) := $(shell $(PKG_CONFIG) --libs $(1) 2>/dev/null) +endef + +# Set FEATURE_CHECK_(C|LD)FLAGS-$(package) for packages using pkg-config. +ifneq ($(PKG_CONFIG),) + $(foreach package,$(FEATURE_PKG_CONFIG),$(call feature_pkg_config,$(package))) +endif + +FEATURE_CHECK_LDFLAGS-libcheck = -lcheck + +# Set FEATURE_CHECK_(C|LD)FLAGS-all for all FEATURE_TESTS features. +# If in the future we need per-feature checks/flags for features not +# mentioned in this list we need to refactor this ;-). +set_test_all_flags = $(eval $(set_test_all_flags_code)) +define set_test_all_flags_code + FEATURE_CHECK_CFLAGS-all += $(FEATURE_CHECK_CFLAGS-$(1)) + FEATURE_CHECK_LDFLAGS-all += $(FEATURE_CHECK_LDFLAGS-$(1)) +endef + +$(foreach feat,$(FEATURE_TESTS),$(call set_test_all_flags,$(feat))) + +# +# Special fast-path for the 'all features are available' case: +# +$(call feature_check,all,$(MSG)) + +# +# Just in case the build freshly failed, make sure we print the +# feature matrix: +# +ifeq ($(feature-all), 1) + # + # test-all.c passed - just set all the core feature flags to 1: + # + $(foreach feat,$(FEATURE_TESTS),$(call feature_set,$(feat))) + # + # test-all.c does not comprise these tests, so we need to + # for this case to get features proper values + # + $(call feature_check,compile-32) + $(call feature_check,compile-x32) + $(call feature_check,bionic) + $(call feature_check,babeltrace2-ctf-writer) + $(call feature_check,libunwind) + $(call feature_check,libunwind-debug-frame) + $(foreach arch,$(LIBUNWIND_ARCHS),$(call feature_check,libunwind-$(arch))) + $(foreach arch,$(LIBUNWIND_ARCHS),$(call feature_check,libunwind-debug-frame-$(arch))) +else + $(foreach feat,$(FEATURE_TESTS),$(call feature_check,$(feat))) +endif + +# +# Print the result of the feature test: +# +feature_print_status = $(eval $(feature_print_status_code)) + +feature_group = $(eval $(feature_gen_group)) $(GROUP) + +define feature_gen_group + GROUP := $(1) + ifneq ($(feature_verbose),1) + GROUP += $(FEATURE_GROUP_MEMBERS-$(1)) + endif +endef + +define feature_print_status_code + ifneq (,$(filter 1,$(foreach feat,$(call feature_group,$(feat)),$(feature-$(feat))))) + MSG = $(shell printf '...%40s: [ \033[32mon\033[m ]' $(1)) + else + MSG = $(shell printf '...%40s: [ \033[31mOFF\033[m ]' $(1)) + endif +endef + +feature_print_text = $(eval $(feature_print_text_code)) +define feature_print_text_code + MSG = $(shell printf '...%40s: %s' $(1) $(2)) +endef + +# +# generates feature value assignment for name, like: +# $(call feature_assign,libdw) == feature-libdw=1 +# +feature_assign = feature-$(1)=$(feature-$(1)) + +FEATURE_DUMP_FILENAME = $(OUTPUT)FEATURE-DUMP$(FEATURE_USER) +FEATURE_DUMP := $(shell touch $(FEATURE_DUMP_FILENAME); cat $(FEATURE_DUMP_FILENAME)) + +feature_dump_check = $(eval $(feature_dump_check_code)) +define feature_dump_check_code + ifeq ($(findstring $(1),$(FEATURE_DUMP)),) + $(2) := 1 + endif +endef + +# +# First check if any test from FEATURE_DISPLAY +# and set feature_display := 1 if it does +$(foreach feat,$(FEATURE_DISPLAY),$(call feature_dump_check,$(call feature_assign,$(feat)),feature_display)) + +# +# Now also check if any other test changed, +# so we force FEATURE-DUMP generation +$(foreach feat,$(FEATURE_TESTS),$(call feature_dump_check,$(call feature_assign,$(feat)),feature_dump_changed)) + +# The $(feature_display) controls the default detection message +# output. It's set if: +# - detected features differes from stored features from +# last build (in $(FEATURE_DUMP_FILENAME) file) +# - one of the $(FEATURE_DISPLAY) is not detected +# - VF is enabled + +ifeq ($(feature_dump_changed),1) + $(shell rm -f $(FEATURE_DUMP_FILENAME)) + $(foreach feat,$(FEATURE_TESTS),$(shell echo "$(call feature_assign,$(feat))" >> $(FEATURE_DUMP_FILENAME))) +endif + +feature_display_check = $(eval $(feature_check_display_code)) +define feature_check_display_code + ifneq ($(feature-$(1)), 1) + feature_display := 1 + endif +endef + +$(foreach feat,$(FEATURE_DISPLAY),$(call feature_display_check,$(feat))) + +ifeq ($(VF),1) + feature_display := 1 + feature_verbose := 1 +endif + +ifneq ($(feature_verbose),1) + # + # Determine the features to omit from the displayed message, as only the + # logical OR of the detection result will be shown. + # + FEATURE_OMIT := $(foreach feat,$(FEATURE_DISPLAY),$(FEATURE_GROUP_MEMBERS-$(feat))) +endif + +feature_display_entries = $(eval $(feature_display_entries_code)) +define feature_display_entries_code + ifeq ($(feature_display),1) + $$(info ) + $$(info Auto-detecting system features:) + $(foreach feat,$(filter-out $(FEATURE_OMIT),$(FEATURE_DISPLAY)),$(call feature_print_status,$(feat),) $$(info $(MSG))) + endif + + ifeq ($(feature_verbose),1) + $(eval TMP := $(filter-out $(FEATURE_DISPLAY),$(FEATURE_TESTS))) + $(foreach feat,$(TMP),$(call feature_print_status,$(feat),) $$(info $(MSG))) + endif +endef + +ifeq ($(FEATURE_DISPLAY_DEFERRED),) + $(call feature_display_entries) + ifeq ($(feature_display),1) + $(info ) + endif +endif -- cgit v1.3.1