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, 346 insertions, 0 deletions

diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
new file mode 100644
index 000000000..b0f7168e7
--- /dev/null
+++ b/tools/bpf/bpftool/Makefile
@@ -0,0 +1,346 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+include ../../scripts/Makefile.include
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+endif
+
+BPF_DIR = $(srctree)/tools/lib/bpf
+
+ifneq ($(OUTPUT),)
+  _OUTPUT := $(OUTPUT)
+else
+  _OUTPUT := $(CURDIR)/
+endif
+BOOTSTRAP_OUTPUT := $(_OUTPUT)bootstrap/
+
+LIBBPF_OUTPUT := $(_OUTPUT)libbpf/
+LIBBPF_DESTDIR := $(LIBBPF_OUTPUT)
+LIBBPF_INCLUDE := $(LIBBPF_DESTDIR)include
+LIBBPF_HDRS_DIR := $(LIBBPF_INCLUDE)/bpf
+LIBBPF := $(LIBBPF_OUTPUT)libbpf.a
+
+LIBBPF_BOOTSTRAP_OUTPUT := $(BOOTSTRAP_OUTPUT)libbpf/
+LIBBPF_BOOTSTRAP_DESTDIR := $(LIBBPF_BOOTSTRAP_OUTPUT)
+LIBBPF_BOOTSTRAP_INCLUDE := $(LIBBPF_BOOTSTRAP_DESTDIR)include
+LIBBPF_BOOTSTRAP_HDRS_DIR := $(LIBBPF_BOOTSTRAP_INCLUDE)/bpf
+LIBBPF_BOOTSTRAP := $(LIBBPF_BOOTSTRAP_OUTPUT)libbpf.a
+
+# We need to copy hashmap.h, nlattr.h, relo_core.h and libbpf_internal.h
+# which are not otherwise exported by libbpf, but still required by bpftool.
+LIBBPF_INTERNAL_HDRS := $(addprefix $(LIBBPF_HDRS_DIR)/,hashmap.h nlattr.h relo_core.h libbpf_internal.h)
+LIBBPF_BOOTSTRAP_INTERNAL_HDRS := $(addprefix $(LIBBPF_BOOTSTRAP_HDRS_DIR)/,hashmap.h relo_core.h libbpf_internal.h)
+
+$(LIBBPF_OUTPUT) $(BOOTSTRAP_OUTPUT) $(LIBBPF_BOOTSTRAP_OUTPUT) $(LIBBPF_HDRS_DIR) $(LIBBPF_BOOTSTRAP_HDRS_DIR):
+	$(QUIET_MKDIR)mkdir -p $@
+
+$(LIBBPF): $(wildcard $(BPF_DIR)/*.[ch] $(BPF_DIR)/Makefile) | $(LIBBPF_OUTPUT)
+	$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_OUTPUT) \
+		DESTDIR=$(LIBBPF_DESTDIR:/=) prefix= $(LIBBPF) install_headers
+
+$(LIBBPF_INTERNAL_HDRS): $(LIBBPF_HDRS_DIR)/%.h: $(BPF_DIR)/%.h | $(LIBBPF_HDRS_DIR)
+	$(call QUIET_INSTALL, $@)
+	$(Q)install -m 644 -t $(LIBBPF_HDRS_DIR) $<
+
+$(LIBBPF_BOOTSTRAP): $(wildcard $(BPF_DIR)/*.[ch] $(BPF_DIR)/Makefile) | $(LIBBPF_BOOTSTRAP_OUTPUT)
+	$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_BOOTSTRAP_OUTPUT) \
+		DESTDIR=$(LIBBPF_BOOTSTRAP_DESTDIR:/=) prefix= \
+		ARCH= CROSS_COMPILE= CC="$(HOSTCC)" LD="$(HOSTLD)" AR="$(HOSTAR)" \
+		CFLAGS="$(LIBBPF_BOOTSTRAP_CFLAGS)" EXTRA_CFLAGS= $@ install_headers
+
+$(LIBBPF_BOOTSTRAP_INTERNAL_HDRS): $(LIBBPF_BOOTSTRAP_HDRS_DIR)/%.h: $(BPF_DIR)/%.h | $(LIBBPF_BOOTSTRAP_HDRS_DIR)
+	$(call QUIET_INSTALL, $@)
+	$(Q)install -m 644 -t $(LIBBPF_BOOTSTRAP_HDRS_DIR) $<
+
+$(LIBBPF)-clean: FORCE | $(LIBBPF_OUTPUT)
+	$(call QUIET_CLEAN, libbpf)
+	$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_OUTPUT) clean >/dev/null
+
+$(LIBBPF_BOOTSTRAP)-clean: FORCE | $(LIBBPF_BOOTSTRAP_OUTPUT)
+	$(call QUIET_CLEAN, libbpf-bootstrap)
+	$(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_BOOTSTRAP_OUTPUT) clean >/dev/null
+
+prefix ?= /usr/local
+bash_compdir ?= /usr/share/bash-completion/completions
+
+CFLAGS += -O2
+CFLAGS += -W
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -Wformat-signedness
+CFLAGS += -Wno-unused-parameter
+CFLAGS += -Wno-missing-field-initializers
+CFLAGS += $(filter-out -Wswitch-enum -Wnested-externs,$(EXTRA_WARNINGS))
+CFLAGS += -DPACKAGE='"bpftool"' -D__EXPORTED_HEADERS__ \
+	-I$(or $(OUTPUT),.) \
+	-I$(LIBBPF_INCLUDE) \
+	-I$(srctree)/kernel/bpf/ \
+	-I$(srctree)/tools/include \
+	-I$(srctree)/tools/include/uapi
+ifneq ($(BPFTOOL_VERSION),)
+CFLAGS += -DBPFTOOL_VERSION='"$(BPFTOOL_VERSION)"'
+endif
+
+# This must be done before appending EXTRA_CFLAGS to CFLAGS to avoid
+# including flags that are not applicable to the host compiler.
+HOST_CFLAGS := $(subst -I$(LIBBPF_INCLUDE),-I$(LIBBPF_BOOTSTRAP_INCLUDE),\
+		$(subst $(CLANG_CROSS_FLAGS),,$(CFLAGS)))
+HOST_CFLAGS += $(HOST_EXTRACFLAGS)
+
+ifneq ($(EXTRA_CFLAGS),)
+CFLAGS += $(EXTRA_CFLAGS)
+endif
+ifneq ($(EXTRA_LDFLAGS),)
+LDFLAGS += $(EXTRA_LDFLAGS)
+endif
+
+HOST_LDFLAGS := $(LDFLAGS)
+
+# Remove warnings for libbpf bootstrap build
+LIBBPF_BOOTSTRAP_CFLAGS := $(filter-out -W -Wall -Wextra -Wformat%,$(HOST_CFLAGS))
+
+INSTALL ?= install
+RM ?= rm -f
+
+FEATURE_USER = .bpftool
+
+# Skip optional dependencies: LLVM (JIT disasm), libbfd (fallback
+# disasm), libcrypto (program signing).
+SKIP_LLVM ?=
+SKIP_LIBBFD ?=
+SKIP_CRYPTO ?=
+ifneq ($(SKIP_CRYPTO),1)
+  CRYPTO_LIBS := -lcrypto
+endif
+
+ifeq ($(MAKECMDGOALS),bootstrap)
+FEATURE_TESTS := libelf-zstd
+FEATURE_DISPLAY :=
+else
+FEATURE_TESTS := clang-bpf-co-re
+FEATURE_TESTS += llvm
+FEATURE_TESTS += libcap
+FEATURE_TESTS += libbfd
+FEATURE_TESTS += libbfd-liberty
+FEATURE_TESTS += libbfd-liberty-z
+FEATURE_TESTS += disassembler-four-args
+FEATURE_TESTS += disassembler-init-styled
+FEATURE_TESTS += libelf-zstd
+
+FEATURE_DISPLAY := clang-bpf-co-re
+FEATURE_DISPLAY += llvm
+FEATURE_DISPLAY += libcap
+FEATURE_DISPLAY += libbfd
+FEATURE_DISPLAY += libbfd-liberty
+FEATURE_DISPLAY += libbfd-liberty-z
+endif
+
+check_feat := 1
+NON_CHECK_FEAT_TARGETS := clean uninstall doc doc-clean doc-install doc-uninstall
+ifdef MAKECMDGOALS
+ifeq ($(filter-out $(NON_CHECK_FEAT_TARGETS),$(MAKECMDGOALS)),)
+  check_feat := 0
+endif
+endif
+
+ifeq ($(check_feat),1)
+ifeq ($(FEATURES_DUMP),)
+include $(srctree)/tools/build/Makefile.feature
+else
+include $(FEATURES_DUMP)
+endif
+endif
+
+LIBS = $(LIBBPF) -lelf $(CRYPTO_LIBS) -lz
+LIBS_BOOTSTRAP = $(LIBBPF_BOOTSTRAP) -lelf $(CRYPTO_LIBS) -lz
+
+ifeq ($(feature-libelf-zstd),1)
+LIBS += -lzstd
+LIBS_BOOTSTRAP += -lzstd
+endif
+
+ifeq ($(feature-libcap), 1)
+CFLAGS += -DUSE_LIBCAP
+LIBS += -lcap
+endif
+
+include $(wildcard $(OUTPUT)*.d)
+
+all: $(OUTPUT)bpftool
+
+SRCS := $(wildcard *.c)
+
+ifeq ($(feature-llvm),1)
+ifneq ($(SKIP_LLVM),1)
+HAS_LLVM := 1
+endif
+endif
+
+ifeq ($(HAS_LLVM),1)
+  CFLAGS  += -DHAVE_LLVM_SUPPORT
+  LLVM_CONFIG_LIB_COMPONENTS := mcdisassembler all-targets
+  # llvm-config always adds -D_GNU_SOURCE, however, it may already be in CFLAGS
+  # (e.g. when bpftool build is called from selftests build as selftests
+  # Makefile includes lib.mk which sets -D_GNU_SOURCE) which would cause
+  # compilation error due to redefinition. Let's filter it out here.
+  CFLAGS  += $(filter-out -D_GNU_SOURCE,$(shell $(LLVM_CONFIG) --cflags))
+  LIBS    += $(shell $(LLVM_CONFIG) --libs $(LLVM_CONFIG_LIB_COMPONENTS))
+  ifeq ($(shell $(LLVM_CONFIG) --shared-mode),static)
+    LIBS += $(shell $(LLVM_CONFIG) --system-libs $(LLVM_CONFIG_LIB_COMPONENTS))
+    LIBS += -lstdc++
+  endif
+  LDFLAGS += $(shell $(LLVM_CONFIG) --ldflags)
+else
+  ifneq ($(SKIP_LIBBFD),1)
+  # Fall back on libbfd
+  ifeq ($(feature-libbfd),1)
+    LIBS += -lbfd -ldl -lopcodes
+  else ifeq ($(feature-libbfd-liberty),1)
+    LIBS += -lbfd -ldl -lopcodes -liberty
+  else ifeq ($(feature-libbfd-liberty-z),1)
+    LIBS += -lbfd -ldl -lopcodes -liberty -lz
+  endif
+
+  # If one of the above feature combinations is set, we support libbfd
+  ifneq ($(filter -lbfd,$(LIBS)),)
+    CFLAGS += -DHAVE_LIBBFD_SUPPORT
+
+    # Libbfd interface changed over time, figure out what we need
+    ifeq ($(feature-disassembler-four-args), 1)
+      CFLAGS += -DDISASM_FOUR_ARGS_SIGNATURE
+    endif
+    ifeq ($(feature-disassembler-init-styled), 1)
+      CFLAGS += -DDISASM_INIT_STYLED
+    endif
+  endif
+  endif # SKIP_LIBBFD
+endif
+ifeq ($(filter -DHAVE_LLVM_SUPPORT -DHAVE_LIBBFD_SUPPORT,$(CFLAGS)),)
+  # No support for JIT disassembly
+  SRCS := $(filter-out jit_disasm.c,$(SRCS))
+endif
+
+ifeq ($(SKIP_CRYPTO),1)
+  CFLAGS += -DBPFTOOL_WITHOUT_CRYPTO
+  HOST_CFLAGS += -DBPFTOOL_WITHOUT_CRYPTO
+  SRCS := $(filter-out sign.c,$(SRCS))
+endif
+
+BPFTOOL_BOOTSTRAP := $(BOOTSTRAP_OUTPUT)bpftool
+
+BOOTSTRAP_OBJS = $(addprefix $(BOOTSTRAP_OUTPUT),main.o common.o json_writer.o gen.o btf.o $(if $(CRYPTO_LIBS),sign.o))
+$(BOOTSTRAP_OBJS): $(LIBBPF_BOOTSTRAP)
+
+OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o
+$(OBJS): $(LIBBPF) $(LIBBPF_INTERNAL_HDRS)
+
+VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux)				\
+		     $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux)	\
+		     ../../../vmlinux					\
+		     /sys/kernel/btf/vmlinux				\
+		     /boot/vmlinux-$(shell uname -r)
+VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
+
+bootstrap: $(BPFTOOL_BOOTSTRAP)
+
+ifneq ($(VMLINUX_BTF)$(VMLINUX_H),)
+ifeq ($(feature-clang-bpf-co-re),1)
+
+BUILD_BPF_SKELS := 1
+
+ifeq ($(VMLINUX_H),)
+$(OUTPUT)vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL_BOOTSTRAP)
+	$(QUIET_GEN)$(BPFTOOL_BOOTSTRAP) btf dump file $< format c > $@
+else
+$(OUTPUT)vmlinux.h: $(VMLINUX_H)
+	$(Q)cp "$(VMLINUX_H)" $@
+endif
+
+$(OUTPUT)%.bpf.o: skeleton/%.bpf.c $(OUTPUT)vmlinux.h $(LIBBPF_BOOTSTRAP)
+	$(QUIET_CLANG)$(CLANG) \
+		-Wno-microsoft-anon-tag \
+		-fms-extensions \
+		-I$(or $(OUTPUT),.) \
+		-I$(srctree)/tools/include/uapi/ \
+		-I$(LIBBPF_BOOTSTRAP_INCLUDE) \
+		-g -O2 -Wall -fno-stack-protector \
+		--target=bpf -c $< -o $@
+	$(Q)$(LLVM_STRIP) -g $@
+
+$(OUTPUT)%.skel.h: $(OUTPUT)%.bpf.o $(BPFTOOL_BOOTSTRAP)
+	$(QUIET_GEN)$(BPFTOOL_BOOTSTRAP) gen skeleton $< > $@
+
+$(OUTPUT)prog.o: $(OUTPUT)profiler.skel.h
+
+$(OUTPUT)pids.o: $(OUTPUT)pid_iter.skel.h
+
+endif
+endif
+
+CFLAGS += $(if $(BUILD_BPF_SKELS),,-DBPFTOOL_WITHOUT_SKELETONS)
+
+$(OUTPUT)disasm.o: $(srctree)/kernel/bpf/disasm.c
+	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD $< -o $@
+
+$(BPFTOOL_BOOTSTRAP): $(BOOTSTRAP_OBJS) $(LIBBPF_BOOTSTRAP)
+	$(QUIET_LINK)$(HOSTCC) $(HOST_CFLAGS) $(HOST_LDFLAGS) $(BOOTSTRAP_OBJS) $(LIBS_BOOTSTRAP) -o $@
+
+$(OUTPUT)bpftool: $(OBJS) $(LIBBPF)
+	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $(OBJS) $(LIBS) -o $@
+
+$(BOOTSTRAP_OUTPUT)%.o: %.c $(LIBBPF_BOOTSTRAP_INTERNAL_HDRS) | $(BOOTSTRAP_OUTPUT)
+	$(QUIET_CC)$(HOSTCC) $(HOST_CFLAGS) -c -MMD $< -o $@
+
+$(OUTPUT)%.o: %.c
+	$(QUIET_CC)$(CC) $(CFLAGS) -c -MMD $< -o $@
+
+feature-detect-clean:
+	$(call QUIET_CLEAN, feature-detect)
+	$(Q)$(MAKE) -C $(srctree)/tools/build/feature/ clean >/dev/null
+
+clean: $(LIBBPF)-clean $(LIBBPF_BOOTSTRAP)-clean feature-detect-clean
+	$(call QUIET_CLEAN, bpftool)
+	$(Q)$(RM) -- $(OUTPUT)bpftool $(OUTPUT)*.o $(OUTPUT)*.d
+	$(Q)$(RM) -- $(OUTPUT)*.skel.h $(OUTPUT)vmlinux.h
+	$(Q)$(RM) -r -- $(LIBBPF_OUTPUT) $(BOOTSTRAP_OUTPUT)
+	$(call QUIET_CLEAN, core-gen)
+	$(Q)$(RM) -- $(OUTPUT)FEATURE-DUMP.bpftool
+	$(Q)$(RM) -r -- $(OUTPUT)feature/
+
+install-bin: $(OUTPUT)bpftool
+	$(call QUIET_INSTALL, bpftool)
+	$(Q)$(INSTALL) -m 0755 -d $(DESTDIR)$(prefix)/sbin
+	$(Q)$(INSTALL) $(OUTPUT)bpftool $(DESTDIR)$(prefix)/sbin/bpftool
+
+install: install-bin
+	$(Q)$(INSTALL) -m 0755 -d $(DESTDIR)$(bash_compdir)
+	$(Q)$(INSTALL) -m 0644 bash-completion/bpftool $(DESTDIR)$(bash_compdir)
+
+uninstall:
+	$(call QUIET_UNINST, bpftool)
+	$(Q)$(RM) -- $(DESTDIR)$(prefix)/sbin/bpftool
+	$(Q)$(RM) -- $(DESTDIR)$(bash_compdir)/bpftool
+
+doc:
+	$(call descend,Documentation)
+
+doc-clean:
+	$(call descend,Documentation,clean)
+
+doc-install:
+	$(call descend,Documentation,install)
+
+doc-uninstall:
+	$(call descend,Documentation,uninstall)
+
+FORCE:
+
+.SECONDARY:
+.PHONY: all FORCE bootstrap clean install-bin install uninstall
+.PHONY: doc doc-clean doc-install doc-uninstall
+.DEFAULT_GOAL := all
+
+# Delete partially updated (corrupted) files on error
+.DELETE_ON_ERROR: