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, 89 insertions, 0 deletions

diff --git a/tools/power/acpi/Makefile.config b/tools/power/acpi/Makefile.config
new file mode 100644
index 000000000..cd7106876
--- /dev/null
+++ b/tools/power/acpi/Makefile.config
@@ -0,0 +1,89 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# tools/power/acpi/Makefile.config - ACPI tool Makefile
+#
+# Copyright (c) 2015, Intel Corporation
+#   Author: Lv Zheng <lv.zheng@intel.com>
+#
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(shell pwd)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+#$(info Determined 'srctree' to be $(srctree))
+endif
+
+include $(srctree)/../../scripts/Makefile.include
+
+OUTPUT=$(srctree)/
+ifeq ("$(origin O)", "command line")
+	OUTPUT := $(O)/tools/power/acpi/
+endif
+#$(info Determined 'OUTPUT' to be $(OUTPUT))
+
+# --- CONFIGURATION BEGIN ---
+
+# Set the following to `true' to make a unstripped, unoptimized
+# binary. Leave this set to `false' for production use.
+DEBUG ?=	true
+
+# make the build silent. Set this to something else to make it noisy again.
+V ?=		false
+
+# Prefix to the directories we're installing to
+DESTDIR ?=
+
+# --- CONFIGURATION END ---
+
+# Directory definitions. These are default and most probably
+# do not need to be changed. Please note that DESTDIR is
+# added in front of any of them
+
+bindir ?=	/usr/bin
+sbindir ?=	/usr/sbin
+mandir ?=	/usr/man
+
+# Toolchain: what tools do we use, and what options do they need:
+
+INSTALL = /usr/bin/install -c
+INSTALL_PROGRAM = ${INSTALL}
+INSTALL_DATA  = ${INSTALL} -m 644
+INSTALL_SCRIPT = ${INSTALL_PROGRAM}
+
+# If you are running a cross compiler, you may want to set this
+# to something more interesting, like "arm-linux-".  If you want
+# to compile vs uClibc, that can be done here as well.
+CROSS = #/usr/i386-linux-uclibc/usr/bin/i386-uclibc-
+CROSS_COMPILE ?= $(CROSS)
+LD = $(CC)
+
+# check if compiler option is supported
+cc-supports = ${shell if $(CC) ${1} -S -o /dev/null -x c /dev/null > /dev/null 2>&1; then echo "$(1)"; fi;}
+
+# use '-Os' optimization if available, else use -O2
+OPTIMIZATION := $(call cc-supports,-Os,-O2)
+
+WARNINGS := -Wall
+WARNINGS += $(call cc-supports,-Wstrict-prototypes)
+WARNINGS += $(call cc-supports,-Wdeclaration-after-statement)
+
+KERNEL_INCLUDE := $(OUTPUT)include
+ACPICA_INCLUDE := $(srctree)/../../../drivers/acpi/acpica
+CFLAGS += -D_LINUX -I$(KERNEL_INCLUDE) -I$(ACPICA_INCLUDE)
+CFLAGS += $(WARNINGS)
+MKDIR = mkdir
+
+ifeq ($(strip $(V)),false)
+	QUIET=@
+	ECHO=@echo
+else
+	QUIET=
+	ECHO=@\#
+endif
+
+# if DEBUG is enabled, then we do not strip or optimize
+ifeq ($(strip $(DEBUG)),true)
+	CFLAGS += -O1 -g -DDEBUG
+	STRIPCMD = /bin/true -Since_we_are_debugging
+else
+	CFLAGS += $(OPTIMIZATION) -fomit-frame-pointer
+	STRIPCMD = $(STRIP) -s --remove-section=.note --remove-section=.comment
+endif