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, 273 insertions, 0 deletions

diff --git a/scripts/package/mkdebian b/scripts/package/mkdebian
new file mode 100755
index 000000000..d4b007b38
--- /dev/null
+++ b/scripts/package/mkdebian
@@ -0,0 +1,273 @@
+#!/bin/sh
+#
+# Copyright 2003 Wichert Akkerman <wichert@wiggy.net>
+#
+# Simple script to generate a debian/ directory for a Linux kernel.
+
+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 "$3"
+	fi
+}
+
+set_debarch() {
+	if [ "${KBUILD_DEBARCH:+set}" ]; then
+		debarch="$KBUILD_DEBARCH"
+		return
+	fi
+
+	# Attempt to find the correct Debian architecture
+	case "$UTS_MACHINE" in
+	i386|alpha|m68k|riscv*)
+		debarch="$UTS_MACHINE" ;;
+	x86_64)
+		debarch=amd64 ;;
+	sparc*)
+		debarch=sparc$(if_enabled_echo CONFIG_64BIT 64) ;;
+	s390*)
+		debarch=s390x ;;
+	ppc*)
+		if is_enabled CONFIG_64BIT; then
+			debarch=ppc64$(if_enabled_echo CONFIG_CPU_LITTLE_ENDIAN el)
+		else
+			debarch=powerpc$(if_enabled_echo CONFIG_SPE spe)
+		fi
+		;;
+	parisc*)
+		debarch=hppa ;;
+	mips*)
+		if is_enabled CONFIG_CPU_LITTLE_ENDIAN; then
+			debarch=mips$(if_enabled_echo CONFIG_64BIT 64)$(if_enabled_echo CONFIG_CPU_MIPSR6 r6)el
+		elif is_enabled CONFIG_CPU_MIPSR6; then
+			debarch=mips$(if_enabled_echo CONFIG_64BIT 64)r6
+		else
+			debarch=mips
+		fi
+		;;
+	aarch64|arm64)
+		debarch=arm64 ;;
+	arm*)
+		if is_enabled CONFIG_AEABI; then
+			debarch=arm$(if_enabled_echo CONFIG_VFP hf el)
+		else
+			debarch=arm
+		fi
+		;;
+	openrisc)
+		debarch=or1k ;;
+	sh)
+		if is_enabled CONFIG_CPU_SH3; then
+			debarch=sh3$(if_enabled_echo CONFIG_CPU_BIG_ENDIAN eb)
+		elif is_enabled CONFIG_CPU_SH4; then
+			debarch=sh4$(if_enabled_echo CONFIG_CPU_BIG_ENDIAN eb)
+		fi
+		;;
+	um)
+		if is_enabled CONFIG_64BIT; then
+			debarch=amd64
+		else
+			debarch=i386
+		fi
+		;;
+	loongarch64)
+		debarch=loong64 ;;
+	esac
+	if [ -z "$debarch" ]; then
+		debarch=$(dpkg-architecture -qDEB_HOST_ARCH)
+		echo "" >&2
+		echo "** ** **  WARNING  ** ** **" >&2
+		echo "" >&2
+		echo "Your architecture doesn't have its equivalent" >&2
+		echo "Debian userspace architecture defined!" >&2
+		echo "Falling back to the current host architecture ($debarch)." >&2
+		echo "Please add support for $UTS_MACHINE to ${0} ..." >&2
+		echo "" >&2
+	fi
+}
+
+# Create debian/source/ if it is a source package build
+gen_source ()
+{
+	mkdir -p debian/source
+
+	echo "3.0 (quilt)" > debian/source/format
+
+	{
+		echo "diff-ignore"
+		echo "extend-diff-ignore = .*"
+	} > debian/source/local-options
+
+	# Add .config as a patch
+	mkdir -p debian/patches
+	{
+		echo "Subject: Add .config"
+		echo "Author: ${maintainer}"
+		echo
+		echo "--- /dev/null"
+		echo "+++ linux/.config"
+		diff -u /dev/null "${KCONFIG_CONFIG}" | tail -n +3
+	} > debian/patches/config.patch
+	echo config.patch > debian/patches/series
+
+	"${srctree}/scripts/package/gen-diff-patch" debian/patches/diff.patch
+	if [ -s debian/patches/diff.patch ]; then
+		sed -i "
+			1iSubject: Add local diff
+			1iAuthor: ${maintainer}
+			1i
+		" debian/patches/diff.patch
+
+		echo diff.patch >> debian/patches/series
+	else
+		rm -f debian/patches/diff.patch
+	fi
+}
+
+rm -rf debian
+mkdir debian
+
+user=${KBUILD_BUILD_USER:-$(id -nu)}
+name=${DEBFULLNAME:-${user}}
+if [ "${DEBEMAIL:+set}" ]; then
+	email=${DEBEMAIL}
+else
+	buildhost=${KBUILD_BUILD_HOST:-$(hostname -f 2>/dev/null || hostname)}
+	email="${user}@${buildhost}"
+fi
+maintainer="${name} <${email}>"
+
+while [ $# -gt 0 ]; do
+	case "$1" in
+	--need-source)
+		gen_source
+		shift
+		;;
+	*)
+		break
+		;;
+	esac
+done
+
+# Some variables and settings used throughout the script
+if [ "${KDEB_PKGVERSION:+set}" ]; then
+	packageversion=$KDEB_PKGVERSION
+else
+	upstream_version=$("${srctree}/scripts/setlocalversion" --no-local "${srctree}" | sed 's/-\(rc[1-9]\)/~\1/')
+	debian_revision=$("${srctree}/scripts/build-version")
+	packageversion=${upstream_version}-${debian_revision}
+fi
+sourcename=${KDEB_SOURCENAME:-linux-upstream}
+
+if [ "$ARCH" = "um" ] ; then
+	packagename=user-mode-linux
+else
+	packagename=linux-image
+fi
+
+debarch=
+set_debarch
+
+# Try to determine distribution
+if [ "${KDEB_CHANGELOG_DIST:+set}" ]; then
+        distribution=$KDEB_CHANGELOG_DIST
+# In some cases lsb_release returns the codename as n/a, which breaks dpkg-parsechangelog
+elif distribution=$(lsb_release -cs 2>/dev/null) && [ -n "$distribution" ] && [ "$distribution" != "n/a" ]; then
+        : # nothing to do in this case
+else
+        distribution="unstable"
+        echo >&2 "Using default distribution of 'unstable' in the changelog"
+        echo >&2 "Install lsb-release or set \$KDEB_CHANGELOG_DIST explicitly"
+fi
+
+echo $debarch > debian/arch
+
+host_gnu=$(dpkg-architecture -a "${debarch}" -q DEB_HOST_GNU_TYPE | sed 's/_/-/g')
+
+# Generate a simple changelog template
+cat <<EOF > debian/changelog
+$sourcename ($packageversion) $distribution; urgency=low
+
+  * Custom built Linux kernel.
+
+ -- $maintainer  $(date -R)
+EOF
+
+# Generate a control file
+cat <<EOF > debian/control
+Source: $sourcename
+Section: kernel
+Priority: optional
+Maintainer: $maintainer
+Rules-Requires-Root: no
+Build-Depends: debhelper-compat (= 12)
+Build-Depends-Arch: bc, bison, flex,
+ gcc-${host_gnu} <!pkg.${sourcename}.nokernelheaders>,
+ kmod, libdw-dev:native, libelf-dev:native,
+ libssl-dev:native, libssl-dev <!pkg.${sourcename}.nokernelheaders>,
+ python3:native, rsync
+Homepage: https://www.kernel.org/
+
+Package: $packagename-${KERNELRELEASE}
+Architecture: $debarch
+Description: Linux kernel, version ${KERNELRELEASE}
+ This package contains the Linux kernel, modules and corresponding other
+ files, version: ${KERNELRELEASE}.
+EOF
+
+if [ "${SRCARCH}" != um ]; then
+cat <<EOF >> debian/control
+
+Package: linux-libc-dev
+Section: devel
+Provides: linux-kernel-headers
+Architecture: $debarch
+Description: Linux support headers for userspace development
+ This package provides userspaces headers from the Linux kernel.  These headers
+ are used by the installed headers for GNU glibc and other system libraries.
+Multi-Arch: same
+EOF
+
+if is_enabled CONFIG_MODULES; then
+cat <<EOF >> debian/control
+
+Package: linux-headers-${KERNELRELEASE}
+Architecture: $debarch
+Build-Profiles: <!pkg.${sourcename}.nokernelheaders>
+Description: Linux kernel headers for ${KERNELRELEASE} on $debarch
+ This package provides kernel header files for ${KERNELRELEASE} on $debarch
+ .
+ This is useful for people who need to build external modules
+EOF
+fi
+fi
+
+if is_enabled CONFIG_DEBUG_INFO; then
+cat <<EOF >> debian/control
+
+Package: linux-image-${KERNELRELEASE}-dbg
+Section: debug
+Architecture: $debarch
+Build-Profiles: <!pkg.${sourcename}.nokerneldbg>
+Description: Linux kernel debugging symbols for ${KERNELRELEASE}
+ This package will come in handy if you need to debug the kernel. It provides
+ all the necessary debug symbols for the kernel and its modules.
+EOF
+fi
+
+cat <<EOF > debian/rules.vars
+ARCH := ${ARCH}
+KERNELRELEASE := ${KERNELRELEASE}
+EOF
+
+cp "${srctree}/scripts/package/debian/copyright" debian/
+cp "${srctree}/scripts/package/debian/rules" debian/
+
+exit 0