[PATCH RFC v2 15/15] selftests/rcutorture: add hazptr torture test script

[Kunwu Chan <kunwu.chan@gmail.com>]

Add hazptr.sh as a one-command regression test for the hazptr
torture configs.

Run NOPREEMPT, PREEMPT, READERS0, and READERS4, followed by
LOCKDEP with wq_churn and SLOWPATH with CONFIG_PROVE_LOCKING=y.
The latter two also check the console for lockdep warnings.

With --allcpus, repeat the PREEMPT test at CPU counts 8, 16, 32,
and so on up to 256.

Follow the pattern of the existing srcu_lockdep.sh script.

Signed-off-by: Kunwu Chan <kunwu.chan@gmail.com>
---
 .../selftests/rcutorture/bin/hazptr.sh        | 146 ++++++++++++++++++
 1 file changed, 146 insertions(+)
 create mode 100755 tools/testing/selftests/rcutorture/bin/hazptr.sh

diff --git a/tools/testing/selftests/rcutorture/bin/hazptr.sh b/tools/testing/selftests/rcutorture/bin/hazptr.sh
new file mode 100755
index 000000000000..ef636e519a55
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/bin/hazptr.sh
@@ -0,0 +1,146 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Run hazptr torture tests and report any that fail.
+#
+# Usage: hazptr.sh [ --cpus N ] [ --allcpus ] [ --datestamp string ]
+#
+# Copyright (C) 2026 Kunwu Chan
+#
+# Authors: Kunwu Chan <kunwu.chan@gmail.com>
+
+usage () {
+	echo "Usage: $scriptname optional arguments:"
+	echo "       --cpus N       override CPU count (default: auto-detect)"
+	echo "       --allcpus      test at CPU counts 8,16,32,...,256"
+	echo "       --datestamp string"
+	exit 1
+}
+
+ds=`date +%Y.%m.%d-%H.%M.%S`-hazptr
+scriptname="$0"
+
+RCUTORTURE="`pwd`/tools/testing/selftests/rcutorture"; export RCUTORTURE
+PATH=${RCUTORTURE}/bin:$PATH; export PATH
+. functions.sh
+
+cpus=""		# empty = let kvm.sh auto-detect
+allcpus=0
+
+while test $# -gt 0
+do
+	case "$1" in
+	--datestamp)
+		checkarg --datestamp "(relative pathname)" "$#" "$2" '^[a-zA-Z0-9._/-]*$' '^--'
+		ds=$2
+		shift
+		;;
+	--cpus)
+		checkarg --cpus "(number)" "$#" "$2" '^[0-9]\+$' '^--'
+		cpus="$2"
+		shift
+		;;
+	--allcpus)
+		allcpus=1
+		;;
+	*)
+		echo Unknown argument $1
+		usage
+		;;
+	esac
+	shift
+done
+
+nerrs=0
+
+run_kvm () {
+	local ds_suffix="$1"
+	local configs="$2"
+	local cpu_arg="$3"
+	local kconfig="$4"
+	local resdir="$RCUTORTURE/res/$ds/$ds_suffix"
+
+	mkdir -p "$resdir"
+
+	tools/testing/selftests/rcutorture/bin/kvm.sh \
+		--torture hazptr \
+		--duration 5s \
+		--configs "$configs" \
+		${cpu_arg:+--cpus "$cpu_arg"} \
+		${kconfig:+--kconfig "$kconfig"} \
+		--trust-make \
+		--datestamp "$ds/$ds_suffix" > "$resdir/kvm.sh.out" 2>&1
+	return $?
+}
+
+check_lockdep () {
+	local ds_suffix="$1" config_dir="$2" label="$3"
+	local resdir="$RCUTORTURE/res/$ds/$ds_suffix"
+	local console="$resdir/$config_dir/console.log"
+
+	if ! test -f "$console"
+	then
+		echo "Missing console.log for $label ($ds_suffix)" > "$resdir/kvm.sh.err"
+		return 1
+	fi
+	if grep -qE "WARNING: possible (recursive locking|circular locking dependency)" "$console"
+	then
+		echo "Lockdep warning in $label" > "$resdir/kvm.sh.err"
+		return 1
+	fi
+	return 0
+}
+
+# Basic torture: all hazptr configs, CPU count auto-detected
+
+echo "--- hazptr basic torture${cpus:+ ($cpus CPUs)} ---"
+run_kvm basic "NOPREEMPT PREEMPT READERS0 READERS4" "$cpus" || nerrs=$((nerrs+1))
+
+# LOCKDEP: verify no lockdep splats with PROVE_LOCKING + wq_churn
+
+echo "--- hazptr lockdep + wq_churn ---"
+if run_kvm lockdep-wq LOCKDEP "$cpus"
+then
+	check_lockdep lockdep-wq LOCKDEP "LOCKDEP wq_churn" ||
+		nerrs=$((nerrs+1))
+else
+	nerrs=$((nerrs+1))
+fi
+
+# SLOWPATH + PROVE_LOCKING: verify forced-slowpath does not deadlock
+
+echo "--- hazptr SLOWPATH + lockdep ---"
+if run_kvm slowpath-lockdep SLOWPATH "$cpus" \
+	"CONFIG_PROVE_LOCKING=y"
+then
+	check_lockdep slowpath-lockdep SLOWPATH \
+		"SLOWPATH+PROVE_LOCKING" ||
+		nerrs=$((nerrs+1))
+else
+	nerrs=$((nerrs+1))
+fi
+
+# CPU scaling: optionally test at multiple CPU counts
+
+if test "$allcpus" -ne 0
+then
+	max_cpus=`grep '^processor' /proc/cpuinfo 2>/dev/null | wc -l`
+	for n in 8 16 32 64 128 256
+	do
+		if test "$n" -le "$max_cpus"
+		then
+		echo "--- hazptr CPU=$n ---"
+		run_kvm "cpu$n" "PREEMPT" "$n" "CONFIG_NR_CPUS=$n" || nerrs=$((nerrs+1))
+		fi
+	done
+fi
+
+# Report
+
+if test "$nerrs" -ne 0
+then
+	echo "hazptr.sh: $nerrs test(s) failed"
+	exit 1
+fi
+echo "hazptr.sh: all tests passed"
+exit 0
-- 
2.43.0