torture: Add clocksource-watchdog testing to torture.sh

This commit adds three short tests of the clocksource-watchdog capability
to the torture.sh script, all to avoid otherwise-inevitable bitrot.
While in the area, fix an obsolete comment.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/testing/selftests/rcutorture/bin/torture.sh

@@ -53,6 +53,7 @@ do_refscale=yes
 do_kvfree=yes
 do_kasan=yes
 do_kcsan=no
+do_clocksourcewd=yes
 
 # doyesno - Helper function for yes/no arguments
 function doyesno () {
@@ -72,6 +73,7 @@ usage () {
 	echo "       --configs-scftorture \"config-file list w/ repeat factor (2*CFLIST)\""
 	echo "       --doall"
 	echo "       --doallmodconfig / --do-no-allmodconfig"
+	echo "       --do-clocksourcewd / --do-no-clocksourcewd"
 	echo "       --do-kasan / --do-no-kasan"
 	echo "       --do-kcsan / --do-no-kcsan"
 	echo "       --do-kvfree / --do-no-kvfree"
@@ -119,10 +121,14 @@ do
 		do_kvfree=yes
 		do_kasan=yes
 		do_kcsan=yes
+		do_clocksourcewd=yes
 		;;
 	--do-allmodconfig|--do-no-allmodconfig)
 		do_allmodconfig=`doyesno "$1" --do-allmodconfig`
 		;;
+	--do-clocksourcewd|--do-no-clocksourcewd)
+		do_clocksourcewd=`doyesno "$1" --do-clocksourcewd`
+		;;
 	--do-kasan|--do-no-kasan)
 		do_kasan=`doyesno "$1" --do-kasan`
 		;;
@@ -145,6 +151,7 @@ do
 		do_kvfree=no
 		do_kasan=no
 		do_kcsan=no
+		do_clocksourcewd=no
 		;;
 	--do-rcuscale|--do-no-rcuscale)
 		do_rcuscale=`doyesno "$1" --do-rcuscale`
@@ -279,9 +286,9 @@ function torture_one {
 #	torture_bootargs="[ kernel boot arguments ]"
 #	torture_set flavor [ kvm.sh arguments ]
 #
-# Note that "flavor" is an arbitrary string.  Supply --torture if needed.
-# Note that quoting is problematic.  So on the command line, pass multiple
-# values with multiple kvm.sh argument instances.
+# Note that "flavor" is an arbitrary string that does not affect kvm.sh
+# in any way.  So also supply --torture if you need something other than
+# the default.
 function torture_set {
 	local cur_kcsan_kmake_args=
 	local kcsan_kmake_tag=
@@ -377,6 +384,22 @@ then
 	torture_set "rcuscale-kvfree" tools/testing/selftests/rcutorture/bin/kvm.sh --torture rcuscale --allcpus --duration 10 --kconfig "CONFIG_NR_CPUS=$HALF_ALLOTED_CPUS" --memory 1G --trust-make
 fi
 
+if test "$do_clocksourcewd" = "yes"
+then
+	torture_bootargs="rcupdate.rcu_cpu_stall_suppress_at_boot=1 torture.disable_onoff_at_boot rcupdate.rcu_task_stall_timeout=30000"
+	torture_set "clocksourcewd-1" tools/testing/selftests/rcutorture/bin/kvm.sh --allcpus --duration 45s --configs TREE03 --kconfig "CONFIG_TEST_CLOCKSOURCE_WATCHDOG=y" --trust-make
+
+	torture_bootargs="rcupdate.rcu_cpu_stall_suppress_at_boot=1 torture.disable_onoff_at_boot rcupdate.rcu_task_stall_timeout=30000 clocksource.max_cswd_read_retries=1"
+	torture_set "clocksourcewd-2" tools/testing/selftests/rcutorture/bin/kvm.sh --allcpus --duration 45s --configs TREE03 --kconfig "CONFIG_TEST_CLOCKSOURCE_WATCHDOG=y" --trust-make
+
+	# In case our work is already done...
+	if test "$do_rcutorture" != "yes"
+	then
+		torture_bootargs="rcupdate.rcu_cpu_stall_suppress_at_boot=1 torture.disable_onoff_at_boot rcupdate.rcu_task_stall_timeout=30000"
+		torture_set "clocksourcewd-3" tools/testing/selftests/rcutorture/bin/kvm.sh --allcpus --duration 45s --configs TREE03 --trust-make
+	fi
+fi
+
 echo " --- " $scriptname $args
 echo " --- " Done `date` | tee -a $T/log
 ret=0