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, 176 insertions, 0 deletions

diff --git a/scripts/package/builddeb b/scripts/package/builddeb
new file mode 100755
index 000000000..ba1defc61
--- /dev/null
+++ b/scripts/package/builddeb
@@ -0,0 +1,176 @@
+#!/bin/sh
+#
+# builddeb 1.3
+# Copyright 2003 Wichert Akkerman <wichert@wiggy.net>
+#
+# Simple script to generate a deb package for a Linux kernel. All the
+# complexity of what to do with a kernel after it is installed or removed
+# is left to other scripts and packages. Scripts can be placed into the
+# preinst, postinst, prerm and postrm directories in /etc/kernel or
+# /usr/share/kernel. A different list of search directories can be given
+# via KDEB_HOOKDIR. Scripts in directories earlier in the list will
+# override scripts of the same name in later directories.  The script will
+# be called on package installation and removal.
+
+set -eu
+
+is_enabled() {
+	grep -q "^$1=y" include/config/auto.conf
+}
+
+if_enabled_echo() {
+	if is_enabled "$1"; then
+		echo -n "$2"
+	elif [ $# -ge 3 ]; then
+		echo -n "$3"
+	fi
+}
+
+install_linux_image () {
+	pname=$1
+	pdir=debian/$1
+
+	# Only some architectures with OF support have this target
+	if is_enabled CONFIG_OF_EARLY_FLATTREE && [ -d "${srctree}/arch/${SRCARCH}/boot/dts" ]; then
+		${MAKE} -f ${srctree}/Makefile INSTALL_DTBS_PATH="${pdir}/usr/lib/linux-image-${KERNELRELEASE}" dtbs_install
+	fi
+
+	${MAKE} -f ${srctree}/Makefile INSTALL_MOD_PATH="${pdir}" INSTALL_MOD_STRIP=1 modules_install
+	rm -f "${pdir}/lib/modules/${KERNELRELEASE}/build"
+
+	# Install the kernel
+	if [ "${ARCH}" = um ] ; then
+		mkdir -p "${pdir}/usr/lib/uml/modules"
+		mv "${pdir}/lib/modules/${KERNELRELEASE}" "${pdir}/usr/lib/uml/modules/${KERNELRELEASE}"
+		mkdir -p "${pdir}/usr/bin" "${pdir}/usr/share/doc/${pname}"
+		cp System.map "${pdir}/usr/lib/uml/modules/${KERNELRELEASE}/System.map"
+		cp ${KCONFIG_CONFIG} "${pdir}/usr/share/doc/${pname}/config"
+		gzip "${pdir}/usr/share/doc/${pname}/config"
+	else
+		mkdir -p "${pdir}/boot"
+		cp System.map "${pdir}/boot/System.map-${KERNELRELEASE}"
+		cp ${KCONFIG_CONFIG} "${pdir}/boot/config-${KERNELRELEASE}"
+	fi
+
+	# Not all arches have the same installed path in debian
+	# XXX: have each arch Makefile export a variable of the canonical image install
+	# path instead
+	case "${SRCARCH}" in
+	um)
+		installed_image_path="usr/bin/linux-${KERNELRELEASE}";;
+	parisc|mips|powerpc)
+		installed_image_path="boot/vmlinux-${KERNELRELEASE}";;
+	*)
+		installed_image_path="boot/vmlinuz-${KERNELRELEASE}";;
+	esac
+	cp "$(${MAKE} -s -f ${srctree}/Makefile image_name)" "${pdir}/${installed_image_path}"
+
+	if [ "${ARCH}" != um ]; then
+		install_maint_scripts "${pdir}"
+	fi
+}
+
+install_maint_scripts () {
+	# Install the maintainer scripts
+	# Note: hook scripts under /etc/kernel are also executed by official Debian
+	# kernel packages, as well as kernel packages built using make-kpkg.
+	# make-kpkg sets $INITRD to indicate whether an initramfs is wanted, and
+	# so do we; recent versions of dracut and initramfs-tools will obey this.
+	debhookdir=${KDEB_HOOKDIR:-/etc/kernel /usr/share/kernel}
+	for script in postinst postrm preinst prerm; do
+		mkdir -p "${pdir}/DEBIAN"
+		cat <<-EOF > "${pdir}/DEBIAN/${script}"
+		#!/bin/sh
+
+		set -e
+
+		# Pass maintainer script parameters to hook scripts
+		export DEB_MAINT_PARAMS="\$*"
+
+		# Tell initramfs builder whether it's wanted
+		export INITRD=$(if_enabled_echo CONFIG_BLK_DEV_INITRD Yes No)
+
+		# run-parts will error out if one of its directory arguments does not
+		# exist, so filter the list of hook directories accordingly.
+		hookdirs=
+		for dir in ${debhookdir}; do
+			test -d "\$dir/${script}.d" || continue
+			hookdirs="\$hookdirs \$dir/${script}.d"
+		done
+		hookdirs="\${hookdirs# }"
+		test -n "\$hookdirs" && run-parts --arg="${KERNELRELEASE}" --arg="/${installed_image_path}" \$hookdirs
+		exit 0
+		EOF
+		chmod 755 "${pdir}/DEBIAN/${script}"
+	done
+}
+
+install_linux_image_dbg () {
+	pdir=debian/$1
+
+	# Parse modules.order directly because 'make modules_install' may sign,
+	# compress modules, and then run unneeded depmod.
+	if is_enabled CONFIG_MODULES; then
+		while read -r mod; do
+			mod="${mod%.o}.ko"
+			dbg="${pdir}/usr/lib/debug/lib/modules/${KERNELRELEASE}/kernel/${mod}"
+			buildid=$("${READELF}" -n "${mod}" | sed -n 's@^.*Build ID: \(..\)\(.*\)@\1/\2@p')
+			link="${pdir}/usr/lib/debug/.build-id/${buildid}.debug"
+
+			mkdir -p "${dbg%/*}" "${link%/*}"
+			"${OBJCOPY}" --only-keep-debug "${mod}" "${dbg}"
+			ln -sf --relative "${dbg}" "${link}"
+		done < modules.order
+	fi
+
+	# Build debug package
+	# Different tools want the image in different locations
+	# perf
+	mkdir -p ${pdir}/usr/lib/debug/lib/modules/${KERNELRELEASE}/
+	cp vmlinux ${pdir}/usr/lib/debug/lib/modules/${KERNELRELEASE}/
+	# systemtap
+	mkdir -p ${pdir}/usr/lib/debug/boot/
+	ln -s ../lib/modules/${KERNELRELEASE}/vmlinux ${pdir}/usr/lib/debug/boot/vmlinux-${KERNELRELEASE}
+	# kdump-tools
+	ln -s lib/modules/${KERNELRELEASE}/vmlinux ${pdir}/usr/lib/debug/vmlinux-${KERNELRELEASE}
+}
+
+install_kernel_headers () {
+	pdir=debian/$1
+	version=${1#linux-headers-}
+
+	# Override $CC only for cross-compiles, to not unnecessarily rebuild
+	# scripts/ including plugins, which may lead to a full kernel rebuild.
+	if [ -n "${CROSS_COMPILE}" ]; then
+		CC="${DEB_HOST_GNU_TYPE}-gcc" "${srctree}/scripts/package/install-extmod-build" "${pdir}/usr/src/linux-headers-${version}"
+	else
+		"${srctree}/scripts/package/install-extmod-build" "${pdir}/usr/src/linux-headers-${version}"
+	fi
+
+	mkdir -p $pdir/lib/modules/$version/
+	ln -s /usr/src/linux-headers-$version $pdir/lib/modules/$version/build
+}
+
+install_libc_headers () {
+	pdir=debian/$1
+
+	$MAKE -f $srctree/Makefile headers_install INSTALL_HDR_PATH=$pdir/usr
+
+	# move asm headers to /usr/include/<libc-machine>/asm to match the structure
+	# used by Debian-based distros (to support multi-arch)
+	mkdir "$pdir/usr/include/${DEB_HOST_MULTIARCH}"
+	mv "$pdir/usr/include/asm" "$pdir/usr/include/${DEB_HOST_MULTIARCH}"
+}
+
+package=$1
+
+case "${package}" in
+*-dbg)
+	install_linux_image_dbg "${package}";;
+linux-image-*|user-mode-linux-*)
+	install_linux_image "${package}";;
+linux-libc-dev)
+	install_libc_headers "${package}";;
+linux-headers-*)
+	install_kernel_headers "${package}";;
+esac