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, 286 insertions, 0 deletions

diff --git a/scripts/coccicheck b/scripts/coccicheck
new file mode 100755
index 000000000..a0a0e0f72
--- /dev/null
+++ b/scripts/coccicheck
@@ -0,0 +1,286 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: GPL-2.0
+# Linux kernel coccicheck
+#
+# Read Documentation/dev-tools/coccinelle.rst
+#
+# This script requires at least spatch
+# version 1.0.0-rc11.
+
+DIR="$(dirname $(readlink -f $0))/.."
+SPATCH="`which ${SPATCH:=spatch}`"
+
+if [ ! -x "$SPATCH" ]; then
+    echo 'spatch is part of the Coccinelle project and is available at https://coccinelle.gitlabpages.inria.fr/website'
+    exit 1
+fi
+
+SPATCH_VERSION=$($SPATCH --version | head -1 | awk '{print $3}')
+
+USE_JOBS="no"
+$SPATCH --help | grep -e "--jobs" > /dev/null && USE_JOBS="yes"
+
+# The verbosity may be set by the environmental parameter V=
+# as for example with 'make V=1 coccicheck'
+
+if [ -n "$V" -a "$V" != "0" ]; then
+	VERBOSE="$V"
+else
+	VERBOSE=0
+fi
+
+FLAGS="--very-quiet"
+
+# You can use SPFLAGS to append extra arguments to coccicheck or override any
+# heuristics done in this file as Coccinelle accepts the last options when
+# options conflict.
+#
+# A good example for use of SPFLAGS is if you want to debug your cocci script,
+# you can for instance use the following:
+#
+# $ export COCCI=scripts/coccinelle/misc/irqf_oneshot.cocci
+# $ make coccicheck MODE=report DEBUG_FILE="all.err" SPFLAGS="--profile --show-trying" M=./drivers/mfd/arizona-irq.c
+#
+# "--show-trying" should show you what rule is being processed as it goes to
+# stdout, you do not need a debug file for that. The profile output will be
+# be sent to stdout, if you provide a DEBUG_FILE the profiling data can be
+# inspected there.
+#
+# --profile will not output if --very-quiet is used, so avoid it.
+echo $SPFLAGS | grep -E -e "--profile|--show-trying" 2>&1 > /dev/null
+if [ $? -eq 0 ]; then
+	FLAGS="--quiet"
+fi
+
+# spatch only allows include directories with the syntax "-I include"
+# while gcc also allows "-Iinclude" and "-include include"
+COCCIINCLUDE=${LINUXINCLUDE//-I/-I }
+COCCIINCLUDE=${COCCIINCLUDE// -include/ --include}
+
+if [ "$C" = "1" -o "$C" = "2" ]; then
+    ONLINE=1
+
+    if [[ $# -le 0 ]]; then
+	    echo ''
+	    echo 'Specifying both the variable "C" and rule "coccicheck" in the make
+command results in a shift count error.'
+	    echo ''
+	    echo 'Try specifying "scripts/coccicheck" as a value for the CHECK variable instead.'
+	    echo ''
+	    echo 'Example:	make C=2 CHECK=scripts/coccicheck drivers/net/ethernet/ethoc.o'
+	    echo ''
+	    exit 1
+    fi
+
+    # Take only the last argument, which is the C file to test
+    shift $(( $# - 1 ))
+    OPTIONS="$COCCIINCLUDE $1"
+
+    # No need to parallelize Coccinelle since this mode takes one input file.
+    NPROC=1
+else
+    ONLINE=0
+    OPTIONS="--dir $srcroot $COCCIINCLUDE"
+
+    # Use only one thread per core by default if hyperthreading is enabled
+    THREADS_PER_CORE=$(LANG=C lscpu | grep "Thread(s) per core: " | tr -cd "[:digit:]")
+    if [ -z "$J" ]; then
+        NPROC=$(getconf _NPROCESSORS_ONLN)
+	if [ $THREADS_PER_CORE -gt 1 -a $NPROC -gt 4 ] ; then
+		NPROC=$((NPROC/2))
+	fi
+    else
+        NPROC="$J"
+    fi
+fi
+
+if [ "$KBUILD_EXTMOD" != "" ] ; then
+    OPTIONS="--patch $srctree $OPTIONS"
+fi
+
+# You can override by using SPFLAGS
+if [ "$USE_JOBS" = "no" ]; then
+	trap kill_running SIGTERM SIGINT
+	declare -a SPATCH_PID
+elif [ "$NPROC" != "1" ]; then
+	# Using 0 should work as well, refer to _SC_NPROCESSORS_ONLN use on
+	# https://github.com/rdicosmo/parmap/blob/master/setcore_stubs.c
+	OPTIONS="$OPTIONS --jobs $NPROC --chunksize 1"
+fi
+
+if [ "$MODE" = "" ] ; then
+    if [ "$ONLINE" = "0" ] ; then
+	echo 'You have not explicitly specified the mode to use. Using default "report" mode.'
+	echo 'Available modes are the following: patch, report, context, org, chain'
+	echo 'You can specify the mode with "make coccicheck MODE=<mode>"'
+	echo 'Note however that some modes are not implemented by some semantic patches.'
+    fi
+    MODE="report"
+fi
+
+if [ "$MODE" = "chain" ] ; then
+    if [ "$ONLINE" = "0" ] ; then
+	echo 'You have selected the "chain" mode.'
+	echo 'All available modes will be tried (in that order): patch, report, context, org'
+    fi
+elif [ "$MODE" = "report" -o "$MODE" = "org" ] ; then
+    FLAGS="--no-show-diff $FLAGS"
+fi
+
+if [ "$ONLINE" = "0" ] ; then
+    echo ''
+    echo 'Please check for false positives in the output before submitting a patch.'
+    echo 'When using "patch" mode, carefully review the patch before submitting it.'
+    echo ''
+fi
+
+run_cmd_parmap() {
+	if [ $VERBOSE -ne 0 ] ; then
+		echo "Running ($NPROC in parallel): $@"
+	fi
+	if [ "$DEBUG_FILE" != "/dev/null" ]; then
+                echo $@>>$DEBUG_FILE
+                $@ 2>>$DEBUG_FILE
+        else
+                echo $@
+                $@ 2>&1
+	fi
+
+	err=$?
+	if [[ $err -ne 0 ]]; then
+		echo "coccicheck failed"
+		exit $err
+	fi
+}
+
+run_cmd_old() {
+	local i
+	if [ $VERBOSE -ne 0 ] ; then
+		echo "Running ($NPROC in parallel): $@"
+	fi
+	for i in $(seq 0 $(( NPROC - 1)) ); do
+		eval "$@ --max $NPROC --index $i &"
+		SPATCH_PID[$i]=$!
+		if [ $VERBOSE -eq 2 ] ; then
+			echo "${SPATCH_PID[$i]} running"
+		fi
+	done
+	wait
+}
+
+run_cmd() {
+	if [ "$USE_JOBS" = "yes" ]; then
+		run_cmd_parmap $@
+	else
+		run_cmd_old $@
+	fi
+}
+
+kill_running() {
+	for i in $(seq 0 $(( NPROC - 1 )) ); do
+		if [ $VERBOSE -eq 2 ] ; then
+			echo "Killing ${SPATCH_PID[$i]}"
+		fi
+		kill ${SPATCH_PID[$i]} 2>/dev/null
+	done
+}
+
+# You can override heuristics with SPFLAGS, these must always go last
+OPTIONS="$OPTIONS $SPFLAGS"
+
+coccinelle () {
+    COCCI="$1"
+
+    OPT=`grep "Options:" $COCCI | cut -d':' -f2`
+    REQ=`grep "Requires:" $COCCI | cut -d':' -f2 | sed "s| ||"`
+    if [ -n "$REQ" ] && ! { echo "$REQ"; echo "$SPATCH_VERSION"; } | sort -CV ; then
+	    echo "Skipping coccinelle SmPL patch: $COCCI"
+	    echo "You have coccinelle:           $SPATCH_VERSION"
+	    echo "This SmPL patch requires:      $REQ"
+	    return
+    fi
+
+#   The option '--parse-cocci' can be used to syntactically check the SmPL files.
+#
+#    $SPATCH -D $MODE $FLAGS -parse_cocci $COCCI $OPT > /dev/null
+
+    if [ $VERBOSE -ne 0 -a $ONLINE -eq 0 ] ; then
+
+	FILE=${COCCI#$srctree/}
+
+	echo "Processing `basename $COCCI`"
+	echo "with option(s) \"$OPT\""
+	echo ''
+	echo 'Message example to submit a patch:'
+
+	sed -ne 's|^///||p' $COCCI
+
+	if [ "$MODE" = "patch" ] ; then
+	    echo ' The semantic patch that makes this change is available'
+	elif [ "$MODE" = "report" ] ; then
+	    echo ' The semantic patch that makes this report is available'
+	elif [ "$MODE" = "context" ] ; then
+	    echo ' The semantic patch that spots this code is available'
+	elif [ "$MODE" = "org" ] ; then
+	    echo ' The semantic patch that makes this Org report is available'
+	else
+	    echo ' The semantic patch that makes this output is available'
+	fi
+	echo " in $FILE."
+	echo ''
+	echo ' More information about semantic patching is available at'
+	echo ' https://coccinelle.gitlabpages.inria.fr/website'
+	echo ''
+
+	if [ "`sed -ne 's|^//#||p' $COCCI`" ] ; then
+	    echo 'Semantic patch information:'
+	    sed -ne 's|^//#||p' $COCCI
+	    echo ''
+	fi
+    fi
+
+    if [ "$MODE" = "chain" ] ; then
+	run_cmd $SPATCH -D patch   \
+		$FLAGS --cocci-file $COCCI $OPT $OPTIONS               || \
+	run_cmd $SPATCH -D report  \
+		$FLAGS --cocci-file $COCCI $OPT $OPTIONS --no-show-diff || \
+	run_cmd $SPATCH -D context \
+		$FLAGS --cocci-file $COCCI $OPT $OPTIONS               || \
+	run_cmd $SPATCH -D org     \
+		$FLAGS --cocci-file $COCCI $OPT $OPTIONS --no-show-diff || exit 1
+    elif [ "$MODE" = "rep+ctxt" ] ; then
+	run_cmd $SPATCH -D report  \
+		$FLAGS --cocci-file $COCCI $OPT $OPTIONS --no-show-diff && \
+	run_cmd $SPATCH -D context \
+		$FLAGS --cocci-file $COCCI $OPT $OPTIONS || exit 1
+    else
+	run_cmd $SPATCH -D $MODE   $FLAGS --cocci-file $COCCI $OPT $OPTIONS || exit 1
+    fi
+
+}
+
+if [ "$DEBUG_FILE" = "" ]; then
+    echo 'You have not explicitly specified the debug file to use.'
+    echo 'Using default "/dev/null" as debug file.'
+    echo 'Debug logs will be printed to stdout.'
+    echo 'You can specify the debug file with "make coccicheck DEBUG_FILE=<debug_file>"'
+    echo ''
+    DEBUG_FILE="/dev/null"
+fi
+
+if [ -f $DEBUG_FILE ]; then
+	echo "Debug file $DEBUG_FILE exists, bailing"
+	exit
+fi
+
+if [ "$COCCI" = "" ] ; then
+    for f in `find $srctree/scripts/coccinelle/ -name '*.cocci' -type f | sort`; do
+        if grep -q "virtual[[:space:]]\+$MODE" "$f"; then
+                coccinelle $f
+        else
+                echo "warning: Skipping $f as it does not match mode '$MODE'"
+        fi
+    done
+else
+    coccinelle $COCCI
+fi