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, 268 insertions, 0 deletions

diff --git a/tools/mm/slabinfo-gnuplot.sh b/tools/mm/slabinfo-gnuplot.sh
new file mode 100644
index 000000000..873a89214
--- /dev/null
+++ b/tools/mm/slabinfo-gnuplot.sh
@@ -0,0 +1,268 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0-only
+
+# Sergey Senozhatsky, 2015
+# sergey.senozhatsky.work@gmail.com
+#
+
+
+# This program is intended to plot a `slabinfo -X' stats, collected,
+# for example, using the following command:
+#   while [ 1 ]; do slabinfo -X >> stats; sleep 1; done
+#
+# Use `slabinfo-gnuplot.sh stats' to pre-process collected records
+# and generate graphs (totals, slabs sorted by size, slabs sorted
+# by size).
+#
+# Graphs can be [individually] regenerate with different ranges and
+# size (-r %d,%d and -s %d,%d options).
+#
+# To visually compare N `totals' graphs, do
+# slabinfo-gnuplot.sh -t FILE1-totals FILE2-totals ... FILEN-totals
+#
+
+min_slab_name_size=11
+xmin=0
+xmax=0
+width=1500
+height=700
+mode=preprocess
+
+usage()
+{
+	echo "Usage: [-s W,H] [-r MIN,MAX] [-t|-l] FILE1 [FILE2 ..]"
+	echo "FILEs must contain 'slabinfo -X' samples"
+	echo "-t 			- plot totals for FILE(s)"
+	echo "-l 			- plot slabs stats for FILE(s)"
+	echo "-s %d,%d		- set image width and height"
+	echo "-r %d,%d		- use data samples from a given range"
+}
+
+check_file_exist()
+{
+	if [ ! -f "$1" ]; then
+		echo "File '$1' does not exist"
+		exit 1
+	fi
+}
+
+do_slabs_plotting()
+{
+	local file=$1
+	local out_file
+	local range="every ::$xmin"
+	local xtic=""
+	local xtic_rotate="norotate"
+	local lines=2000000
+	local wc_lines
+
+	check_file_exist "$file"
+
+	out_file=`basename "$file"`
+	if [ $xmax -ne 0 ]; then
+		range="$range::$xmax"
+		lines=$((xmax-xmin))
+	fi
+
+	wc_lines=`cat "$file" | wc -l`
+	if [ $? -ne 0 ] || [ "$wc_lines" -eq 0 ] ; then
+		wc_lines=$lines
+	fi
+
+	if [ "$wc_lines" -lt "$lines" ]; then
+		lines=$wc_lines
+	fi
+
+	if [ $((width / lines)) -gt $min_slab_name_size ]; then
+		xtic=":xtic(1)"
+		xtic_rotate=90
+	fi
+
+gnuplot -p << EOF
+#!/usr/bin/env gnuplot
+
+set terminal png enhanced size $width,$height large
+set output '$out_file.png'
+set autoscale xy
+set xlabel 'samples'
+set ylabel 'bytes'
+set style histogram columnstacked title textcolor lt -1
+set style fill solid 0.15
+set xtics rotate $xtic_rotate
+set key left above Left title reverse
+
+plot "$file" $range u 2$xtic title 'SIZE' with boxes,\
+	'' $range u 3 title 'LOSS' with boxes
+EOF
+
+	if [ $? -eq 0 ]; then
+		echo "$out_file.png"
+	fi
+}
+
+do_totals_plotting()
+{
+	local gnuplot_cmd=""
+	local range="every ::$xmin"
+	local file=""
+
+	if [ $xmax -ne 0 ]; then
+		range="$range::$xmax"
+	fi
+
+	for i in "${t_files[@]}"; do
+		check_file_exist "$i"
+
+		file="$file"`basename "$i"`
+		gnuplot_cmd="$gnuplot_cmd '$i' $range using 1 title\
+			'$i Memory usage' with lines,"
+		gnuplot_cmd="$gnuplot_cmd '' $range using 2 title \
+			'$i Loss' with lines,"
+	done
+
+gnuplot -p << EOF
+#!/usr/bin/env gnuplot
+
+set terminal png enhanced size $width,$height large
+set autoscale xy
+set output '$file.png'
+set xlabel 'samples'
+set ylabel 'bytes'
+set key left above Left title reverse
+
+plot $gnuplot_cmd
+EOF
+
+	if [ $? -eq 0 ]; then
+		echo "$file.png"
+	fi
+}
+
+do_preprocess()
+{
+	local out
+	local lines
+	local in=$1
+
+	check_file_exist "$in"
+
+	# use only 'TOP' slab (biggest memory usage or loss)
+	let lines=3
+	out=`basename "$in"`"-slabs-by-loss"
+	`cat "$in" | grep -A "$lines" 'Slabs sorted by loss' |\
+		grep -E -iv '\-\-|Name|Slabs'\
+		| awk '{print $1" "$4+$2*$3" "$4}' > "$out"`
+	if [ $? -eq 0 ]; then
+		do_slabs_plotting "$out"
+	fi
+
+	let lines=3
+	out=`basename "$in"`"-slabs-by-size"
+	`cat "$in" | grep -A "$lines" 'Slabs sorted by size' |\
+		grep -E -iv '\-\-|Name|Slabs'\
+		| awk '{print $1" "$4" "$4-$2*$3}' > "$out"`
+	if [ $? -eq 0 ]; then
+		do_slabs_plotting "$out"
+	fi
+
+	out=`basename "$in"`"-totals"
+	`cat "$in" | grep "Memory used" |\
+		awk '{print $3" "$7}' > "$out"`
+	if [ $? -eq 0 ]; then
+		t_files[0]=$out
+		do_totals_plotting
+	fi
+}
+
+parse_opts()
+{
+	local opt
+
+	while getopts "tlr::s::h" opt; do
+		case $opt in
+			t)
+				mode=totals
+				;;
+			l)
+				mode=slabs
+				;;
+			s)
+				array=(${OPTARG//,/ })
+				width=${array[0]}
+				height=${array[1]}
+				;;
+			r)
+				array=(${OPTARG//,/ })
+				xmin=${array[0]}
+				xmax=${array[1]}
+				;;
+			h)
+				usage
+				exit 0
+				;;
+			\?)
+				echo "Invalid option: -$OPTARG" >&2
+				exit 1
+				;;
+			:)
+				echo "-$OPTARG requires an argument." >&2
+				exit 1
+				;;
+		esac
+	done
+
+	return $OPTIND
+}
+
+parse_args()
+{
+	local idx=0
+	local p
+
+	for p in "$@"; do
+		case $mode in
+			preprocess)
+				files[$idx]=$p
+				idx=$idx+1
+				;;
+			totals)
+				t_files[$idx]=$p
+				idx=$idx+1
+				;;
+			slabs)
+				files[$idx]=$p
+				idx=$idx+1
+				;;
+		esac
+	done
+}
+
+parse_opts "$@"
+argstart=$?
+parse_args "${@:$argstart}"
+
+if [ ${#files[@]} -eq 0 ] && [ ${#t_files[@]} -eq 0 ]; then
+	usage
+	exit 1
+fi
+
+case $mode in
+	preprocess)
+		for i in "${files[@]}"; do
+			do_preprocess "$i"
+		done
+		;;
+	totals)
+		do_totals_plotting
+		;;
+	slabs)
+		for i in "${files[@]}"; do
+			do_slabs_plotting "$i"
+		done
+		;;
+	*)
+		echo "Unknown mode $mode" >&2
+		usage
+		exit 1
+	;;
+esac