ftrace: Synchronize the initialization of ftrace_opsgrafted

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 <rostedt@goodmis.org>

1 files changed, 397 insertions, 0 deletions

diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
new file mode 100644
index 000000000..7d1650181
--- /dev/null
+++ b/tools/build/feature/Makefile
@@ -0,0 +1,397 @@
+# SPDX-License-Identifier: GPL-2.0
+include ../../scripts/Makefile.include
+
+LIBUNWIND_ARCHS:=aarch64 arm loongarch64 mips ppc32 ppc64 riscv s390x x86 x86_64
+
+FILES=                                          \
+         test-all.bin                           \
+         test-backtrace.bin                     \
+         test-bionic.bin                        \
+         test-libdw.bin                         \
+         test-eventfd.bin                       \
+         test-fortify-source.bin                \
+         test-glibc.bin                         \
+         test-gtk2.bin                          \
+         test-gtk2-infobar.bin                  \
+         test-hello.bin                         \
+         test-libbfd.bin                        \
+	 test-libbfd-threadsafe.bin      	\
+         test-disassembler-four-args.bin        \
+         test-disassembler-init-styled.bin	\
+         test-reallocarray.bin			\
+         test-libbfd-liberty.bin                \
+         test-libbfd-liberty-z.bin              \
+         test-cplus-demangle.bin                \
+         test-cxa-demangle.bin                  \
+         test-libcap.bin			\
+         test-libelf.bin                        \
+         test-libelf-getphdrnum.bin             \
+         test-libelf-gelf_getnote.bin           \
+         test-libelf-getshdrstrndx.bin          \
+         test-libelf-zstd.bin                   \
+         test-libdebuginfod.bin                 \
+         test-libnuma.bin                       \
+         test-numa_num_possible_cpus.bin        \
+         test-libperl.bin                       \
+         test-libpython.bin                     \
+         test-libslang.bin                      \
+         test-libtraceevent.bin                 \
+         test-libcpupower.bin                   \
+         test-libtracefs.bin                    \
+         test-libunwind.bin                     \
+         test-libunwind-debug-frame.bin         \
+         $(foreach arch,$(LIBUNWIND_ARCHS),test-libunwind-$(arch).bin test-libunwind-debug-frame-$(arch).bin) \
+         test-pthread-attr-setaffinity-np.bin   \
+         test-pthread-barrier.bin		\
+         test-stackprotector-all.bin            \
+         test-timerfd.bin                       \
+         test-babeltrace2-ctf-writer.bin        \
+         test-libcapstone.bin			\
+         test-libcheck.bin			\
+         test-compile-32.bin                    \
+         test-compile-x32.bin                   \
+         test-zlib.bin                          \
+         test-lzma.bin                          \
+         test-bpf.bin                           \
+         test-libbpf.bin                        \
+         test-sdt.bin                           \
+         test-gettid.bin			\
+         test-jvmti.bin				\
+         test-jvmti-cmlr.bin			\
+         test-scandirat.bin			\
+         test-sched_getcpu.bin			\
+         test-setns.bin				\
+         test-libopencsd.bin			\
+         test-llvm.bin				\
+         test-llvm-perf.bin   			\
+         test-libaio.bin			\
+         test-libzstd.bin			\
+         test-clang-bpf-co-re.bin		\
+         test-file-handle.bin			\
+         test-libpfm4.bin			\
+         test-rust.bin				\
+         test-libopenssl.bin			\
+         test-bpftool-skeletons.bin
+
+FILES := $(addprefix $(OUTPUT),$(FILES))
+
+# Some distros provide the command $(CROSS_COMPILE)pkg-config for
+# searching packges installed with Multiarch. Use it for cross
+# compilation if it is existed.
+ifneq (, $(shell which $(CROSS_COMPILE)pkg-config))
+  PKG_CONFIG ?= $(CROSS_COMPILE)pkg-config
+else
+  PKG_CONFIG ?= pkg-config
+
+  # PKG_CONFIG_PATH or PKG_CONFIG_LIBDIR, alongside PKG_CONFIG_SYSROOT_DIR
+  # for modified system root, are required for the cross compilation.
+  # If these PKG_CONFIG environment variables are not set, Multiarch library
+  # paths are used instead.
+  ifdef CROSS_COMPILE
+    ifeq ($(PKG_CONFIG_LIBDIR)$(PKG_CONFIG_PATH)$(PKG_CONFIG_SYSROOT_DIR),)
+      CROSS_ARCH = $(notdir $(CROSS_COMPILE:%-=%))
+      PKG_CONFIG_LIBDIR := /usr/local/$(CROSS_ARCH)/lib/pkgconfig/
+      PKG_CONFIG_LIBDIR := $(PKG_CONFIG_LIBDIR):/usr/local/lib/$(CROSS_ARCH)/pkgconfig/
+      PKG_CONFIG_LIBDIR := $(PKG_CONFIG_LIBDIR):/usr/lib/$(CROSS_ARCH)/pkgconfig/
+      PKG_CONFIG_LIBDIR := $(PKG_CONFIG_LIBDIR):/usr/local/share/pkgconfig/
+      PKG_CONFIG_LIBDIR := $(PKG_CONFIG_LIBDIR):/usr/share/pkgconfig/
+      export PKG_CONFIG_LIBDIR
+    endif
+  endif
+endif
+
+ifeq ($(findstring -static,${LDFLAGS}),-static)
+  PKG_CONFIG += --static
+endif
+
+all: $(FILES)
+
+__BUILD = $(CC) $(CFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.c,$(@F)) $(LDFLAGS)
+  BUILD = $(__BUILD) > $(@:.bin=.make.output) 2>&1
+  BUILD_BFD = $(BUILD) -DPACKAGE='"perf"' -lbfd -ldl
+  BUILD_ALL = $(BUILD) -fstack-protector-all -O2 -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -lslang \
+	      $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -ldl -lz -llzma -lzstd \
+	      $(shell $(PKG_CONFIG) --libs --cflags openssl 2>/dev/null)
+
+__BUILDXX = $(CXX) $(CXXFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$(@F)) $(LDFLAGS)
+  BUILDXX = $(__BUILDXX) > $(@:.bin=.make.output) 2>&1
+
+###############################
+
+$(OUTPUT)test-all.bin:
+	$(BUILD_ALL)
+
+$(OUTPUT)test-hello.bin:
+	$(BUILD)
+
+$(OUTPUT)test-pthread-attr-setaffinity-np.bin:
+	$(BUILD) -D_GNU_SOURCE -lpthread
+
+$(OUTPUT)test-pthread-barrier.bin:
+	$(BUILD) -lpthread
+
+$(OUTPUT)test-stackprotector-all.bin:
+	$(BUILD) -fstack-protector-all
+
+$(OUTPUT)test-fortify-source.bin:
+	$(BUILD) -O2 -D_FORTIFY_SOURCE=2
+
+$(OUTPUT)test-bionic.bin:
+	$(BUILD)
+
+$(OUTPUT)test-libcap.bin:
+	$(BUILD) -lcap
+
+$(OUTPUT)test-libelf.bin:
+	$(BUILD) -lelf
+
+$(OUTPUT)test-eventfd.bin:
+	$(BUILD)
+
+$(OUTPUT)test-glibc.bin:
+	$(BUILD)
+
+$(OUTPUT)test-scandirat.bin:
+	$(BUILD)
+
+$(OUTPUT)test-sched_getcpu.bin:
+	$(BUILD)
+
+$(OUTPUT)test-setns.bin:
+	$(BUILD)
+
+$(OUTPUT)test-libopencsd.bin:
+	$(BUILD) # -lopencsd_c_api -lopencsd provided by
+		 # $(FEATURE_CHECK_LDFLAGS-libopencsd)
+
+DWLIBS := -ldw
+ifeq ($(findstring -static,${LDFLAGS}),-static)
+  DWLIBS += -lelf -lz -llzma -lbz2 -lzstd
+
+  LIBDW_VERSION := $(shell $(PKG_CONFIG) --modversion libdw).0.0
+  LIBDW_VERSION_1 := $(word 1, $(subst ., ,$(LIBDW_VERSION)))
+  LIBDW_VERSION_2 := $(word 2, $(subst ., ,$(LIBDW_VERSION)))
+
+  # Elfutils merged libebl.a into libdw.a starting from version 0.177,
+  # Link libebl.a only if libdw is older than this version.
+  ifeq ($(shell test $(LIBDW_VERSION_2) -lt 177; echo $$?),0)
+    DWLIBS += -lebl
+  endif
+
+  # Must put -ldl after -lebl for dependency
+  DWARFLIBS += -ldl
+endif
+
+$(OUTPUT)test-libdw.bin:
+	$(BUILD) $(DWLIBS)
+
+$(OUTPUT)test-libelf-getphdrnum.bin:
+	$(BUILD) -lelf
+
+$(OUTPUT)test-libelf-gelf_getnote.bin:
+	$(BUILD) -lelf
+
+$(OUTPUT)test-libelf-getshdrstrndx.bin:
+	$(BUILD) -lelf
+
+$(OUTPUT)test-libelf-zstd.bin:
+	$(BUILD) -lelf -lz -lzstd
+
+$(OUTPUT)test-libdebuginfod.bin:
+	$(BUILD) -ldebuginfod
+
+$(OUTPUT)test-libnuma.bin:
+	$(BUILD) -lnuma
+
+$(OUTPUT)test-numa_num_possible_cpus.bin:
+	$(BUILD) -lnuma
+
+$(OUTPUT)test-libunwind.bin:
+	$(BUILD) -include libunwind.h -lelf -llzma -lunwind
+
+$(OUTPUT)test-libunwind-debug-frame.bin:
+	$(BUILD) -include libunwind.h -lelf -llzma -lunwind
+
+define LIBUNWIND_RULE
+$$(OUTPUT)test-libunwind-$(1).bin:
+	$$(CC) $$(CFLAGS) -MD -Wall -Werror -include libunwind-$(1).h -o $$@ \
+		test-libunwind.c $$(LDFLAGS) -lelf -llzma -lunwind-$(1) \
+		> $$(@:.bin=.make.output) 2>&1
+
+$$(OUTPUT)test-libunwind-debug-frame-$(1).bin:
+	$$(CC) $$(CFLAGS) -MD -Wall -Werror -include libunwind-$(1).h -o $$@ \
+		test-libunwind-debug-frame.c $$(LDFLAGS) -lelf -llzma -lunwind-$(1) \
+		> $$(@:.bin=.make.output) 2>&1
+
+endef
+$(foreach arch,$(LIBUNWIND_ARCHS), \
+    $(eval $(call LIBUNWIND_RULE,$(arch))) \
+)
+
+$(OUTPUT)test-libslang.bin:
+	$(BUILD) -lslang
+
+$(OUTPUT)test-libtraceevent.bin:
+	$(BUILD) -ltraceevent
+
+$(OUTPUT)test-libcpupower.bin:
+	$(BUILD) -lcpupower
+
+$(OUTPUT)test-libtracefs.bin:
+	 $(BUILD) $(shell $(PKG_CONFIG) --cflags libtracefs 2>/dev/null) -ltracefs
+
+$(OUTPUT)test-gtk2.bin:
+	$(BUILD) $(shell $(PKG_CONFIG) --libs --cflags gtk+-2.0 2>/dev/null) -Wno-deprecated-declarations
+
+$(OUTPUT)test-gtk2-infobar.bin:
+	$(BUILD) $(shell $(PKG_CONFIG) --libs --cflags gtk+-2.0 2>/dev/null)
+
+grep-libs  = $(filter -l%,$(1))
+strip-libs = $(filter-out -l%,$(1))
+
+PERL_EMBED_LDOPTS = $(shell perl -MExtUtils::Embed -e ldopts 2>/dev/null)
+PERL_EMBED_LDFLAGS = $(call strip-libs,$(PERL_EMBED_LDOPTS))
+PERL_EMBED_LIBADD = $(call grep-libs,$(PERL_EMBED_LDOPTS))
+PERL_EMBED_CCOPTS = $(shell perl -MExtUtils::Embed -e ccopts 2>/dev/null)
+FLAGS_PERL_EMBED=$(PERL_EMBED_CCOPTS) $(PERL_EMBED_LDOPTS)
+
+ifeq ($(CC_NO_CLANG), 0)
+  PERL_EMBED_LDOPTS := $(filter-out -specs=%,$(PERL_EMBED_LDOPTS))
+  PERL_EMBED_CCOPTS := $(filter-out -flto=auto -ffat-lto-objects, $(PERL_EMBED_CCOPTS))
+  PERL_EMBED_CCOPTS := $(filter-out -specs=%,$(PERL_EMBED_CCOPTS))
+  FLAGS_PERL_EMBED += -Wno-compound-token-split-by-macro
+endif
+
+$(OUTPUT)test-libperl.bin:
+	$(BUILD) $(FLAGS_PERL_EMBED)
+
+$(OUTPUT)test-libpython.bin:
+	$(BUILD) $(FLAGS_PYTHON_EMBED)
+
+$(OUTPUT)test-libbfd.bin:
+	$(BUILD_BFD)
+
+$(OUTPUT)test-libbfd-threadsafe.bin:
+	$(BUILD_BFD) || $(BUILD_BFD) -liberty || $(BUILD_BFD) -liberty -lz
+
+$(OUTPUT)test-disassembler-four-args.bin:
+	$(BUILD_BFD) -lopcodes || $(BUILD_BFD) -lopcodes -liberty || \
+	$(BUILD_BFD) -lopcodes -liberty -lz
+
+$(OUTPUT)test-disassembler-init-styled.bin:
+	$(BUILD_BFD) -lopcodes || $(BUILD_BFD) -lopcodes -liberty || \
+	$(BUILD_BFD) -lopcodes -liberty -lz
+
+$(OUTPUT)test-reallocarray.bin:
+	$(BUILD)
+
+$(OUTPUT)test-libbfd-liberty.bin:
+	$(CC) $(CFLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty
+
+$(OUTPUT)test-libbfd-liberty-z.bin:
+	$(CC) $(CFLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty -lz
+
+$(OUTPUT)test-cplus-demangle.bin:
+	$(BUILD) -liberty
+
+$(OUTPUT)test-cxa-demangle.bin:
+	$(BUILDXX)
+
+$(OUTPUT)test-backtrace.bin:
+	$(BUILD)
+
+$(OUTPUT)test-timerfd.bin:
+	$(BUILD)
+
+$(OUTPUT)test-babeltrace2-ctf-writer.bin:
+	$(BUILD) # -lbabeltrace2-ctf-writer provided by $(FEATURE_CHECK_LDFLAGS-babeltrace2-ctf-writer)
+
+$(OUTPUT)test-libcapstone.bin:
+	$(BUILD) # -lcapstone provided by $(FEATURE_CHECK_LDFLAGS-libcapstone)
+
+$(OUTPUT)test-libcheck.bin:
+	$(BUILD) # -lcheck is provided by $(FEATURE_CHECK_LDFLAGS-libcheck)
+
+$(OUTPUT)test-compile-32.bin:
+	$(CC) -m32 -Wall -Werror -o $@ test-compile.c
+
+$(OUTPUT)test-compile-x32.bin:
+	$(CC) -mx32 -Wall -Werror -o $@ test-compile.c
+
+$(OUTPUT)test-zlib.bin:
+	$(BUILD) -lz
+
+$(OUTPUT)test-lzma.bin:
+	$(BUILD) -llzma
+
+$(OUTPUT)test-bpf.bin:
+	$(BUILD)
+
+$(OUTPUT)test-libbpf.bin:
+	$(BUILD) -lbpf
+
+$(OUTPUT)test-sdt.bin:
+	$(BUILD)
+
+$(OUTPUT)test-gettid.bin:
+	$(BUILD)
+
+$(OUTPUT)test-jvmti.bin:
+	$(BUILD)
+
+$(OUTPUT)test-jvmti-cmlr.bin:
+	$(BUILD)
+
+$(OUTPUT)test-llvm.bin:
+	$(BUILDXX) -std=gnu++17 				\
+		-I$(shell $(LLVM_CONFIG) --includedir) 		\
+		-L$(shell $(LLVM_CONFIG) --libdir)		\
+		$(shell $(LLVM_CONFIG) --libs Core BPF)		\
+		$(shell $(LLVM_CONFIG) --system-libs)		\
+		> $(@:.bin=.make.output) 2>&1
+
+$(OUTPUT)test-llvm-perf.bin:
+	$(BUILDXX) -std=gnu++17 				\
+		-I$(shell $(LLVM_CONFIG) --includedir) 		\
+		-L$(shell $(LLVM_CONFIG) --libdir)		\
+		$(shell $(LLVM_CONFIG) --libs Core BPF)		\
+		$(shell $(LLVM_CONFIG) --system-libs)		\
+		> $(@:.bin=.make.output) 2>&1
+
+-include $(OUTPUT)*.d
+
+$(OUTPUT)test-libaio.bin:
+	$(BUILD) -lrt
+
+$(OUTPUT)test-libzstd.bin:
+	$(BUILD) -lzstd
+
+$(OUTPUT)test-clang-bpf-co-re.bin: test-clang-bpf-co-re.c
+	{ $(CLANG) -S -g --target=bpf -o - $< |	\
+		grep BTF_KIND_VAR; } > $(@:.bin=.make.output) 2>&1 && touch $@
+
+$(OUTPUT)test-file-handle.bin:
+	$(BUILD)
+
+$(OUTPUT)test-libpfm4.bin:
+	$(BUILD) -lpfm
+
+$(OUTPUT)test-libopenssl.bin:
+	$(BUILD) $(shell $(PKG_CONFIG) --libs --cflags openssl 2>/dev/null)
+
+$(OUTPUT)test-bpftool-skeletons.bin:
+	{ $(SYSTEM_BPFTOOL) version | grep '^features:.*skeletons'; } \
+		> $(@:.bin=.make.output) 2>&1 && touch $@
+
+# Testing Rust is special: we don't compile anything, it's enough to check the
+# compiler presence. Compiling a test code for this purposes is problematic,
+# because Rust will emit a dependency file without any external references,
+# meaning that if rustc will be removed the build process will still think it's
+# there.
+$(OUTPUT)test-rust.bin:
+	$(RUSTC) --version > /dev/null 2>&1
+
+###############################
+
+clean:
+	rm -f $(FILES) $(OUTPUT)*.d $(FILES:.bin=.make.output)