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, 146 insertions, 0 deletions

diff --git a/tools/perf/perf-archive.sh b/tools/perf/perf-archive.sh
new file mode 100755
index 000000000..7977e9b0a
--- /dev/null
+++ b/tools/perf/perf-archive.sh
@@ -0,0 +1,146 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# perf archive
+# Arnaldo Carvalho de Melo <acme@redhat.com>
+
+PERF_DATA=perf.data
+PERF_SYMBOLS=perf.symbols
+PERF_ALL=perf.all
+ALL=0
+UNPACK=0
+
+while [ $# -gt 0 ] ; do
+	if [ $1 == "--all" ]; then
+		ALL=1
+		shift
+	elif [ $1 == "--unpack" ]; then
+		UNPACK=1
+		shift
+	elif [ $1 == "--exclude-buildids" ]; then
+		EXCLUDE_BUILDIDS="$2"
+		if [ ! -e "$EXCLUDE_BUILDIDS" ]; then
+			echo "Provided exclude-buildids file $EXCLUDE_BUILDIDS does not exist"
+			exit 1
+		fi
+		shift 2
+	else
+		PERF_DATA=$1
+		UNPACK_TAR=$1
+		shift
+	fi
+done
+
+if [ $UNPACK -eq 1 ]; then
+	if [ ! -z "$UNPACK_TAR" ]; then					# tar given as an argument
+		if [ ! -e "$UNPACK_TAR" ]; then
+			echo "Provided file $UNPACK_TAR does not exist"
+			exit 1
+		fi
+		TARGET="$UNPACK_TAR"
+	else																# search for perf tar in the current directory
+		TARGET=`find . -regex "\./perf.*\.tar\.bz2"`
+		TARGET_NUM=`echo -n "$TARGET" | grep -c '^'`
+
+		if [ -z "$TARGET" ] || [ $TARGET_NUM -gt 1 ]; then
+			echo -e "Error: $TARGET_NUM files found for unpacking:\n$TARGET"
+			echo "Provide the requested file as an argument"
+			exit 1
+		else
+			echo "Found target file for unpacking: $TARGET"
+		fi
+	fi
+
+	if [[ "$TARGET" =~ (\./)?$PERF_ALL.*.tar.bz2 ]]; then				# perf tar generated by --all option
+		TAR_CONTENTS=`tar tvf "$TARGET" | tr -s " " | cut -d " " -f 6`
+		VALID_TAR=`echo "$TAR_CONTENTS" | grep "$PERF_SYMBOLS.tar.bz2" | wc -l`		# check if it contains a sub-tar perf.symbols
+		if [ $VALID_TAR -ne 1 ]; then
+			echo "Error: $TARGET file is not valid (contains zero or multiple sub-tar files with debug symbols)"
+			exit 1
+		fi
+
+		INTERSECT=`comm -12 <(ls) <(echo "$TAR_CONTENTS") | tr "\n" " "`	# check for overwriting
+		if [ ! -z "$INTERSECT" ]; then										# prompt if file(s) already exist in the current directory
+			echo "File(s) ${INTERSECT::-1} already exist in the current directory."
+			while true; do
+				read -p 'Do you wish to overwrite them? ' yn
+				case $yn in
+					[Yy]* ) break;;
+					[Nn]* ) exit 1;;
+					* ) echo "Please answer yes or no.";;
+				esac
+			done
+		fi
+
+		# unzip the perf.data file in the current working directory	and debug symbols in ~/.debug directory
+		tar xvf $TARGET && tar xvf $PERF_SYMBOLS.tar.bz2 -C ~/.debug
+
+	else																# perf tar generated by perf archive (contains only debug symbols)
+		tar xvf $TARGET -C ~/.debug
+	fi
+	exit 0
+fi
+
+#
+# PERF_BUILDID_DIR environment variable set by perf
+# path to buildid directory, default to $HOME/.debug
+#
+if [ -z $PERF_BUILDID_DIR ]; then
+	PERF_BUILDID_DIR=~/.debug/
+else
+        # append / to make substitutions work
+        PERF_BUILDID_DIR=$PERF_BUILDID_DIR/
+fi
+
+BUILDIDS=$(mktemp /tmp/perf-archive-buildids.XXXXXX)
+
+#
+# EXCLUDE_BUILDIDS is an optional file that contains build-ids to be excluded from the
+# archive. It is a list of build-ids, one per line, without any leading or trailing spaces.
+# If the file is empty, all build-ids will be included in the archive. To create a exclude-
+# buildids file, you can use the following command:
+# 	perf buildid-list -i perf.data --with-hits | grep -v "^ " > exclude_buildids.txt
+# You can edit the file to remove the lines that you want to keep in the archive, then:
+# 	perf archive --exclude-buildids exclude_buildids.txt
+#
+if [ -s "$EXCLUDE_BUILDIDS" ]; then
+	perf buildid-list -i $PERF_DATA --with-hits | grep -v "^ " | grep -Fv -f $EXCLUDE_BUILDIDS > $BUILDIDS
+	if [ ! -s "$BUILDIDS" ] ; then
+		echo "perf archive: no build-ids found after applying exclude-buildids file"
+		rm $BUILDIDS || true
+		exit 1
+	fi
+else
+	perf buildid-list -i $PERF_DATA --with-hits | grep -v "^ " > $BUILDIDS
+	if [ ! -s "$BUILDIDS" ] ; then
+		echo "perf archive: no build-ids found"
+		rm $BUILDIDS || true
+		exit 1
+	fi
+fi
+
+MANIFEST=$(mktemp /tmp/perf-archive-manifest.XXXXXX)
+PERF_BUILDID_LINKDIR=$(readlink -f $PERF_BUILDID_DIR)/
+
+cut -d ' ' -f 1 $BUILDIDS | \
+while read build_id ; do
+	linkname=$PERF_BUILDID_DIR.build-id/${build_id:0:2}/${build_id:2}
+	filename=$(readlink -f $linkname)
+	echo ${linkname#$PERF_BUILDID_DIR} >> $MANIFEST
+	echo ${filename#$PERF_BUILDID_LINKDIR} >> $MANIFEST
+done
+
+if [ $ALL -eq 1 ]; then						# pack perf.data file together with tar containing debug symbols
+	HOSTNAME=$(hostname)
+	DATE=$(date '+%Y%m%d-%H%M%S')
+	tar cjf $PERF_SYMBOLS.tar.bz2 -C $PERF_BUILDID_DIR -T $MANIFEST
+	tar cjf	$PERF_ALL-$HOSTNAME-$DATE.tar.bz2 $PERF_DATA $PERF_SYMBOLS.tar.bz2
+	rm $PERF_SYMBOLS.tar.bz2 $MANIFEST $BUILDIDS || true
+else										# pack only the debug symbols
+	tar cjf $PERF_DATA.tar.bz2 -C $PERF_BUILDID_DIR -T $MANIFEST
+	rm $MANIFEST $BUILDIDS || true
+fi
+
+echo -e "Now please run:\n"
+echo -e "$ perf archive --unpack\n"
+echo "or unpack the tar manually wherever you need to run 'perf report' on."
+exit 0