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, 234 insertions, 0 deletions

diff --git a/tools/perf/check-headers.sh b/tools/perf/check-headers.sh
new file mode 100755
index 000000000..531c0e0e8
--- /dev/null
+++ b/tools/perf/check-headers.sh
@@ -0,0 +1,234 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+YELLOW='\033[0;33m'
+NC='\033[0m' # No Color
+
+declare -a FILES=(
+  "include/uapi/linux/const.h"
+  "include/uapi/linux/bits.h"
+  "include/uapi/linux/fscrypt.h"
+  "include/uapi/linux/genetlink.h"
+  "include/uapi/linux/if_addr.h"
+  "include/uapi/linux/in.h"
+  "include/uapi/linux/kcmp.h"
+  "include/uapi/linux/kvm.h"
+  "include/uapi/linux/neighbour.h"
+  "include/uapi/linux/netfilter.h"
+  "include/uapi/linux/netfilter_arp.h"
+  "include/uapi/linux/perf_event.h"
+  "include/uapi/linux/rtnetlink.h"
+  "include/uapi/linux/seccomp.h"
+  "include/uapi/linux/stat.h"
+  "include/linux/bits.h"
+  "include/vdso/bits.h"
+  "include/linux/cfi_types.h"
+  "include/linux/const.h"
+  "include/vdso/const.h"
+  "include/vdso/unaligned.h"
+  "include/linux/gfp_types.h"
+  "include/linux/hash.h"
+  "include/linux/list-sort.h"
+  "include/uapi/linux/hw_breakpoint.h"
+  "arch/x86/include/asm/cpufeatures.h"
+  "arch/x86/include/asm/inat_types.h"
+  "arch/x86/include/asm/emulate_prefix.h"
+  "arch/x86/include/asm/msr-index.h"
+  "arch/x86/lib/x86-opcode-map.txt"
+  "arch/x86/tools/gen-insn-attr-x86.awk"
+  "arch/arm/include/uapi/asm/perf_regs.h"
+  "arch/arm64/include/uapi/asm/perf_regs.h"
+  "arch/loongarch/include/uapi/asm/perf_regs.h"
+  "arch/mips/include/uapi/asm/perf_regs.h"
+  "arch/powerpc/include/uapi/asm/perf_regs.h"
+  "arch/s390/include/uapi/asm/perf_regs.h"
+  "arch/x86/include/uapi/asm/perf_regs.h"
+  "arch/x86/include/uapi/asm/kvm.h"
+  "arch/x86/include/uapi/asm/svm.h"
+  "arch/x86/include/uapi/asm/unistd.h"
+  "arch/x86/include/uapi/asm/vmx.h"
+  "arch/powerpc/include/uapi/asm/kvm.h"
+  "arch/s390/include/uapi/asm/kvm.h"
+  "arch/s390/include/uapi/asm/sie.h"
+  "arch/arm64/include/uapi/asm/kvm.h"
+  "arch/alpha/include/uapi/asm/errno.h"
+  "arch/mips/include/asm/errno.h"
+  "arch/mips/include/uapi/asm/errno.h"
+  "arch/parisc/include/uapi/asm/errno.h"
+  "arch/powerpc/include/uapi/asm/errno.h"
+  "arch/sparc/include/uapi/asm/errno.h"
+  "arch/x86/include/uapi/asm/errno.h"
+  "include/asm-generic/bitops/arch_hweight.h"
+  "include/asm-generic/bitops/const_hweight.h"
+  "include/asm-generic/bitops/__fls.h"
+  "include/asm-generic/bitops/fls.h"
+  "include/asm-generic/bitops/fls64.h"
+  "include/linux/coresight-pmu.h"
+  "include/uapi/asm-generic/errno.h"
+  "include/uapi/asm-generic/errno-base.h"
+  "include/uapi/asm-generic/ioctls.h"
+  "include/uapi/asm-generic/mman-common.h"
+  "include/uapi/asm-generic/unistd.h"
+  "scripts/syscall.tbl"
+)
+
+declare -a SYNC_CHECK_FILES=(
+  "arch/x86/include/asm/inat.h"
+  "arch/x86/include/asm/insn.h"
+  "arch/x86/lib/inat.c"
+  "arch/x86/lib/insn.c"
+)
+
+# These copies are under tools/perf/trace/beauty/ as they are not used to in
+# building object files only by scripts in tools/perf/trace/beauty/ to generate
+# tables that then gets included in .c files for things like id->string syscall
+# tables (and the reverse lookup as well: string -> id)
+
+declare -a BEAUTY_FILES=(
+  "arch/x86/include/asm/irq_vectors.h"
+  "arch/x86/include/uapi/asm/prctl.h"
+  "include/uapi/drm/drm.h"
+  "include/uapi/drm/i915_drm.h"
+  "include/linux/socket.h"
+  "include/uapi/linux/fadvise.h"
+  "include/uapi/linux/fcntl.h"
+  "include/uapi/linux/fs.h"
+  "include/uapi/linux/mount.h"
+  "include/uapi/linux/prctl.h"
+  "include/uapi/linux/sched.h"
+  "include/uapi/linux/stat.h"
+  "include/uapi/linux/usbdevice_fs.h"
+  "include/uapi/linux/vhost.h"
+  "include/uapi/sound/asound.h"
+)
+
+declare -a FAILURES
+
+check_2 () {
+  tools_file=$1
+  orig_file=$2
+
+  shift
+  shift
+
+  cmd="diff $* $tools_file $orig_file > /dev/null"
+
+  if [ -f "$orig_file" ] && ! eval "$cmd"
+  then
+    FAILURES+=(
+      "$tools_file $orig_file"
+    )
+  fi
+}
+
+check () {
+  file=$1
+
+  shift
+
+  check_2 "tools/$file" "$file" "$@"
+}
+
+beauty_check () {
+  file=$1
+
+  shift
+
+  check_2 "tools/perf/trace/beauty/$file" "$file" "$@"
+}
+
+check_ignore_some_hunks () {
+  orig_file="$1"
+  tools_file="tools/$orig_file"
+  hunks_to_ignore="tools/perf/check-header_ignore_hunks/$orig_file"
+
+  if [ ! -f "$hunks_to_ignore" ]; then
+    echo "$hunks_to_ignore not found. Skipping $orig_file check."
+    FAILURES+=(
+      "$tools_file $orig_file"
+    )
+    return
+  fi
+
+  cmd="diff -u \"$tools_file\" \"$orig_file\" | grep -vf \"$hunks_to_ignore\" | wc -l | grep -qw 0"
+
+  if [ -f "$orig_file" ] && ! eval "$cmd"
+  then
+    FAILURES+=(
+      "$tools_file $orig_file"
+    )
+  fi
+}
+
+
+# Check if we have the kernel headers (tools/perf/../../include), else
+# we're probably on a detached tarball, so no point in trying to check
+# differences.
+if ! [ -d ../../include ]
+then
+  echo -e "${YELLOW}Warning${NC}: Skipped check-headers due to missing ../../include"
+  exit 0
+fi
+
+cd ../..
+
+# simple diff check
+for i in "${FILES[@]}"
+do
+  check "$i" -B
+done
+
+for i in "${SYNC_CHECK_FILES[@]}"
+do
+  check "$i" '-I "^.*\/\*.*__ignore_sync_check__.*\*\/.*$"'
+done
+
+# diff with extra ignore lines
+check arch/x86/lib/memcpy_64.S        '-I "^EXPORT_SYMBOL" -I "^#include <asm/export.h>" -I"^SYM_FUNC_START\(_LOCAL\)*(memcpy_\(erms\|orig\))" -I"^#include <linux/cfi_types.h>"'
+check arch/x86/lib/memset_64.S        '-I "^EXPORT_SYMBOL" -I "^#include <asm/export.h>" -I"^SYM_FUNC_START\(_LOCAL\)*(memset_\(erms\|orig\))"'
+check arch/x86/include/asm/amd/ibs.h  '-I "^#include .*/msr-index.h"'
+check include/linux/unaligned.h '-I "^#include <linux/unaligned/packed_struct.h>" -I "^#include <asm/byteorder.h>" -I "^#pragma GCC diagnostic"'
+check include/uapi/asm-generic/mman.h '-I "^#include <\(uapi/\)*asm-generic/mman-common\(-tools\)*.h>"'
+check include/uapi/linux/mman.h       '-I "^#include <\(uapi/\)*asm/mman.h>"'
+check include/linux/build_bug.h       '-I "^#\(ifndef\|endif\)\( \/\/\)* static_assert$"'
+check include/linux/ctype.h	      '-I "isdigit("'
+check lib/ctype.c		      '-I "^EXPORT_SYMBOL" -I "^#include <linux/export.h>" -B'
+
+# diff non-symmetric files
+check_2 tools/perf/arch/x86/entry/syscalls/syscall_32.tbl arch/x86/entry/syscalls/syscall_32.tbl
+check_2 tools/perf/arch/x86/entry/syscalls/syscall_64.tbl arch/x86/entry/syscalls/syscall_64.tbl
+check_2 tools/perf/arch/powerpc/entry/syscalls/syscall.tbl arch/powerpc/kernel/syscalls/syscall.tbl
+check_2 tools/perf/arch/s390/entry/syscalls/syscall.tbl arch/s390/kernel/syscalls/syscall.tbl
+check_2 tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl arch/mips/kernel/syscalls/syscall_n64.tbl
+check_2 tools/perf/arch/arm/entry/syscalls/syscall.tbl arch/arm/tools/syscall.tbl
+check_2 tools/perf/arch/sh/entry/syscalls/syscall.tbl arch/sh/kernel/syscalls/syscall.tbl
+check_2 tools/perf/arch/sparc/entry/syscalls/syscall.tbl arch/sparc/kernel/syscalls/syscall.tbl
+check_2 tools/perf/arch/xtensa/entry/syscalls/syscall.tbl arch/xtensa/kernel/syscalls/syscall.tbl
+check_2 tools/perf/arch/alpha/entry/syscalls/syscall.tbl arch/alpha/entry/syscalls/syscall.tbl
+check_2 tools/perf/arch/parisc/entry/syscalls/syscall.tbl arch/parisc/entry/syscalls/syscall.tbl
+check_2 tools/perf/arch/arm64/entry/syscalls/syscall_32.tbl arch/arm64/entry/syscalls/syscall_32.tbl
+check_2 tools/perf/arch/arm64/entry/syscalls/syscall_64.tbl arch/arm64/entry/syscalls/syscall_64.tbl
+
+for i in "${BEAUTY_FILES[@]}"
+do
+  beauty_check "$i" -B
+done
+
+# check duplicated library files
+check_2 tools/perf/util/hashmap.h tools/lib/bpf/hashmap.h
+check_2 tools/perf/util/hashmap.c tools/lib/bpf/hashmap.c
+
+# Files with larger differences
+
+check_ignore_some_hunks lib/list_sort.c
+
+cd tools/perf || exit
+
+if [ ${#FAILURES[@]} -gt 0 ]
+then
+  echo -e "${YELLOW}Warning${NC}: Kernel ABI header differences:"
+  for i in "${FAILURES[@]}"
+  do
+    echo "  diff -u $i"
+  done
+fi