Torture-test changes for 3.16

From: "Paul E. McKenney" <[email protected]>

The rcutorture output currently does not distinguish between stalls in the RCU implementation and stalls in the rcu_torture_writer() kthreads. This commit therefore adds some diagnostics to help distinguish between these two conditions, at least for the non-SRCU implementations. (SRCU does not provide evidence of update-side forward progress by design.)

Signed-off-by Paul E. McKenney <[email protected]>

 include/linux/rcupdate.h | 19 +++++++++++++++++++
 kernel/rcu/rcutorture.c  | 37 +++++++++++++++++++++++++++++++++++++
 kernel/rcu/tree.c        | 18 ++++++++++++++++++
 3 files changed, 74 insertions(+)

include/linux/rcupdate.h +19 -0

index 00a7fd61b3c6..a6c3898e141e 100644
@@ -51,7 +51,17 @@ extern int rcu_expedited; /* for sysctl */
 extern int rcutorture_runnable; /* for sysctl */
 #endif /* #ifdef CONFIG_RCU_TORTURE_TEST */
 
+enum rcutorture_type {
+	RTORT_BUSTED,
+	RTORT_RCU,
+	RTORT_RCU_BH,
+	RTORT_RCU_SCHED,
+	RTORT_SRCU
+};
+
 #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
+void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
+			    unsigned long *gpnum, unsigned long *completed);
 void rcutorture_record_test_transition(void);
 void rcutorture_record_progress(unsigned long vernum);
 void do_trace_rcu_torture_read(const char *rcutorturename,

@@ -60,6 +70,15 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
 			       unsigned long c_old,
 			       unsigned long c);
 #else
+static inline void rcutorture_get_gp_data(enum rcutorture_type test_type,
+					  int *flags,
+					  unsigned long *gpnum,
+					  unsigned long *completed)
+{
+	*flags = 0;
+	*gpnum = 0;
+	*completed = 0;
+}
 static inline void rcutorture_record_test_transition(void)
 {
 }

kernel/rcu/rcutorture.c +37 -0

index bd30bc61bc05..1110db210318 100644
@@ -138,6 +138,15 @@ static long n_barrier_attempts;
 static long n_barrier_successes;
 static struct list_head rcu_torture_removed;
 
+static int rcu_torture_writer_state;
+#define RTWS_FIXED_DELAY	0
+#define RTWS_DELAY		1
+#define RTWS_REPLACE		2
+#define RTWS_DEF_FREE		3
+#define RTWS_EXP_SYNC		4
+#define RTWS_STUTTER		5
+#define RTWS_STOPPING		6
+
 #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
 #define RCUTORTURE_RUNNABLE_INIT 1
 #else

@@ -214,6 +223,7 @@ rcu_torture_free(struct rcu_torture *p)
  */
 
 struct rcu_torture_ops {
+	int ttype;
 	void (*init)(void);
 	int (*readlock)(void);
 	void (*read_delay)(struct torture_random_state *rrsp);

@@ -312,6 +322,7 @@ static void rcu_sync_torture_init(void)
 }
 
 static struct rcu_torture_ops rcu_ops = {
+	.ttype		= RTORT_RCU,
 	.init		= rcu_sync_torture_init,
 	.readlock	= rcu_torture_read_lock,
 	.read_delay	= rcu_read_delay,

@@ -355,6 +366,7 @@ static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
 }
 
 static struct rcu_torture_ops rcu_bh_ops = {
+	.ttype		= RTORT_RCU_BH,
 	.init		= rcu_sync_torture_init,
 	.readlock	= rcu_bh_torture_read_lock,
 	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */

@@ -397,6 +409,7 @@ call_rcu_busted(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
 }
 
 static struct rcu_torture_ops rcu_busted_ops = {
+	.ttype		= RTORT_BUSTED,
 	.init		= rcu_sync_torture_init,
 	.readlock	= rcu_torture_read_lock,
 	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */

@@ -492,6 +505,7 @@ static void srcu_torture_synchronize_expedited(void)
 }
 
 static struct rcu_torture_ops srcu_ops = {
+	.ttype		= RTORT_SRCU,
 	.init		= rcu_sync_torture_init,
 	.readlock	= srcu_torture_read_lock,
 	.read_delay	= srcu_read_delay,

@@ -527,6 +541,7 @@ static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
 }
 
 static struct rcu_torture_ops sched_ops = {
+	.ttype		= RTORT_RCU_SCHED,
 	.init		= rcu_sync_torture_init,
 	.readlock	= sched_torture_read_lock,
 	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */

@@ -699,12 +714,15 @@ rcu_torture_writer(void *arg)
 	set_user_nice(current, MAX_NICE);
 
 	do {
+		rcu_torture_writer_state = RTWS_FIXED_DELAY;
 		schedule_timeout_uninterruptible(1);
 		rp = rcu_torture_alloc();
 		if (rp == NULL)
 			continue;
 		rp->rtort_pipe_count = 0;
+		rcu_torture_writer_state = RTWS_DELAY;
 		udelay(torture_random(&rand) & 0x3ff);
+		rcu_torture_writer_state = RTWS_REPLACE;
 		old_rp = rcu_dereference_check(rcu_torture_current,
 					       current == writer_task);
 		rp->rtort_mbtest = 1;

@@ -721,8 +739,10 @@ rcu_torture_writer(void *arg)
 			else
 				exp = gp_exp;
 			if (!exp) {
+				rcu_torture_writer_state = RTWS_DEF_FREE;
 				cur_ops->deferred_free(old_rp);
 			} else {
+				rcu_torture_writer_state = RTWS_EXP_SYNC;
 				cur_ops->exp_sync();
 				list_add(&old_rp->rtort_free,
 					 &rcu_torture_removed);

@@ -743,8 +763,10 @@ rcu_torture_writer(void *arg)
 			}
 		}
 		rcutorture_record_progress(++rcu_torture_current_version);
+		rcu_torture_writer_state = RTWS_STUTTER;
 		stutter_wait("rcu_torture_writer");
 	} while (!torture_must_stop());
+	rcu_torture_writer_state = RTWS_STOPPING;
 	torture_kthread_stopping("rcu_torture_writer");
 	return 0;
 }

@@ -937,6 +959,7 @@ rcu_torture_printk(char *page)
 	int i;
 	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
 	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
+	static unsigned long rtcv_snap = ULONG_MAX;
 
 	for_each_possible_cpu(cpu) {
 		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {

@@ -997,6 +1020,20 @@ rcu_torture_printk(char *page)
 	page += sprintf(page, "\n");
 	if (cur_ops->stats)
 		cur_ops->stats(page);
+	if (rtcv_snap == rcu_torture_current_version &&
+	    rcu_torture_current != NULL) {
+		int __maybe_unused flags;
+		unsigned long __maybe_unused gpnum;
+		unsigned long __maybe_unused completed;
+
+		rcutorture_get_gp_data(cur_ops->ttype,
+				       &flags, &gpnum, &completed);
+		page += sprintf(page,
+				"??? Writer stall state %d g%lu c%lu f%#x\n",
+				rcu_torture_writer_state,
+				gpnum, completed, flags);
+	}
+	rtcv_snap = rcu_torture_current_version;
 }
 
 /*

kernel/rcu/tree.c +18 -0

index 0c47e300210a..032106df7391 100644
@@ -294,6 +294,24 @@ void rcutorture_record_test_transition(void)
 EXPORT_SYMBOL_GPL(rcutorture_record_test_transition);
 
 /*
+ * Send along grace-period-related data for rcutorture diagnostics.
+ */
+void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
+			    unsigned long *gpnum, unsigned long *completed)
+{
+	if (test_type == RTORT_SRCU || test_type == RTORT_BUSTED) {
+		*flags = 0;
+		*gpnum = 0;
+		*completed = 0;
+		return;
+	}
+	*flags = ACCESS_ONCE(rcu_state->gp_flags);
+	*gpnum = ACCESS_ONCE(rcu_state->gpnum);
+	*completed = ACCESS_ONCE(rcu_state->completed);
+}
+EXPORT_SYMBOL_GPL(rcutorture_get_gp_data);
+
+/*
  * Record the number of writer passes through the current rcutorture test.
  * This is also used to correlate debugfs tracing stats with the rcutorture
  * messages.

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

The current lock_torture_writer() spends too much time sleeping and not enough time hammering locks, as in an eight-CPU test will often only be utilizing a CPU or two. This commit therefore makes lock_torture_writer() sleep less and hammer more.

Signed-off-by Paul E. McKenney <[email protected]>

---
 kernel/locking/locktorture.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

kernel/locking/locktorture.c +0 -0

index f26b1a18e34e..b0d3e3c50672 100644

kernel/locking/locktorture.c +0 -0

 		cur_ops->writelock();
 		if (WARN_ON_ONCE(lock_is_write_held))
 			lwsp->n_write_lock_fail++;

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

Some environments require some variation on "make defconfig" to initialize the .config file. This commit therefore adds a --defconfig argument to allow this to be specified. The default value is of course "defconfig".

Signed-off-by Paul E. McKenney <[email protected]>

 tools/testing/selftests/rcutorture/bin/configinit.sh | 2 +-
 tools/testing/selftests/rcutorture/bin/kvm.sh        | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

tools/testing/selftests/rcutorture/bin/configinit.sh +1 -1

index a1be6e62add1..9c3f3d39b934 100755
@@ -62,7 +62,7 @@ grep '^grep' < $T/u.sh > $T/upd.sh
 echo "cat - $c" >> $T/upd.sh
 make mrproper
 make $buildloc distclean > $builddir/Make.distclean 2>&1
-make $buildloc defconfig > $builddir/Make.defconfig.out 2>&1
+make $buildloc $TORTURE_DEFCONFIG > $builddir/Make.defconfig.out 2>&1
 mv $builddir/.config $builddir/.config.sav
 sh $T/upd.sh < $builddir/.config.sav > $builddir/.config
 cp $builddir/.config $builddir/.config.new

tools/testing/selftests/rcutorture/bin/kvm.sh +8 -0

index a52a077ee258..59945b7793d9 100644
@@ -38,6 +38,7 @@ dur=30
 dryrun=""
 KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
 PATH=${KVM}/bin:$PATH; export PATH
+TORTURE_DEFCONFIG=defconfig
 TORTURE_INITRD="$KVM/initrd"; export TORTURE_INITRD
 RCU_KMAKE_ARG=""; export RCU_KMAKE_ARG
 TORTURE_SUITE=rcu

@@ -56,6 +57,7 @@ usage () {
 	echo "       --configs \"config-file list\""
 	echo "       --cpus N"
 	echo "       --datestamp string"
+	echo "       --defconfig string"
 	echo "       --dryrun sched|script"
 	echo "       --duration minutes"
 	echo "       --interactive"

@@ -96,6 +98,11 @@ do
 		ds=$2
 		shift
 		;;
+	--defconfig)
+		checkarg --defconfig "defconfigtype" "$#" "$2" '^[^/][^/]*$' '^--'
+		TORTURE_DEFCONFIG=$2
+		shift
+		;;
 	--dryrun)
 		checkarg --dryrun "sched|script" $# "$2" 'sched\|script' '^--'
 		dryrun=$2

@@ -259,6 +266,7 @@ END {
 # Generate a script to execute the tests in appropriate batches.
 cat << ___EOF___ > $T/script
 TORTURE_SUITE="$TORTURE_SUITE"; export TORTURE_SUITE
+TORTURE_DEFCONFIG="$TORTURE_DEFCONFIG"; export TORTURE_DEFCONFIG
 ___EOF___
 awk < $T/cfgcpu.pack \
 	-v CONFIGDIR="$CONFIGFRAG/$kversion/" \

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

This commit makes the torture scripts a bit more RCU-independent.

Signed-off-by Paul E. McKenney <[email protected]>

---
 tools/testing/selftests/rcutorture/bin/kvm-build.sh | 2 +-
 tools/testing/selftests/rcutorture/bin/kvm.sh       | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

tools/testing/selftests/rcutorture/bin/kvm-build.sh +1 -1

index d8e68a5e4411..e838c775f709 100755
@@ -60,7 +60,7 @@ then
 	exit 2
 fi
 ncpus=`cpus2use.sh`
-make O=$builddir -j$ncpus $RCU_KMAKE_ARG > $builddir/Make.out 2>&1
+make O=$builddir -j$ncpus $TORTURE_KMAKE_ARG > $builddir/Make.out 2>&1
 retval=$?
 if test $retval -ne 0 || grep "rcu[^/]*": < $builddir/Make.out | egrep -q "Stop|Error|error:|warning:" || egrep -q "Stop|Error|error:" < $builddir/Make.out
 then

tools/testing/selftests/rcutorture/bin/kvm.sh +3 -3

index 59945b7793d9..04ad1f980dfe 100644
@@ -40,7 +40,7 @@ KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
 PATH=${KVM}/bin:$PATH; export PATH
 TORTURE_DEFCONFIG=defconfig
 TORTURE_INITRD="$KVM/initrd"; export TORTURE_INITRD
-RCU_KMAKE_ARG=""; export RCU_KMAKE_ARG
+TORTURE_KMAKE_ARG=""
 TORTURE_SUITE=rcu
 resdir=""
 configs=""

@@ -118,7 +118,7 @@ do
 		;;
 	--kmake-arg)
 		checkarg --kmake-arg "(kernel make arguments)" $# "$2" '.*' '^error$'
-		RCU_KMAKE_ARG="$2"; export RCU_KMAKE_ARG
+		TORTURE_KMAKE_ARG="$2"
 		shift
 		;;
 	--kversion)

@@ -376,7 +376,7 @@ then
 	echo PATH="$PATH; export PATH"
 	echo RCU_BUILDONLY="$RCU_BUILDONLY; export RCU_BUILDONLY"
 	echo TORTURE_INITRD="$TORTURE_INITRD; export TORTURE_INITRD"
-	echo RCU_KMAKE_ARG="$RCU_KMAKE_ARG; export RCU_KMAKE_ARG"
+	echo TORTURE_KMAKE_ARG="$TORTURE_KMAKE_ARG; export TORTURE_KMAKE_ARG"
 	echo RCU_QEMU_CMD="$RCU_QEMU_CMD; export RCU_QEMU_CMD"
 	echo RCU_QEMU_INTERACTIVE="$RCU_QEMU_INTERACTIVE; export RCU_QEMU_INTERACTIVE"
 	echo RCU_QEMU_MAC="$RCU_QEMU_MAC; export RCU_QEMU_MAC"

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

This commit makes the torture scripts a bit more RCU-independent.

Signed-off-by Paul E. McKenney <[email protected]>

---
 tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh | 2 +-
 tools/testing/selftests/rcutorture/bin/kvm.sh            | 9 ++++++---
 2 files changed, 7 insertions(+), 4 deletions(-)

tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh +1 -1

index e82f4f201c8c..86e6ffe6df45 100755
@@ -152,7 +152,7 @@ boot_args="`configfrag_boot_params "$boot_args" "$config_template"`"
 boot_args="`per_version_boot_params "$boot_args" $builddir/.config $seconds`"
 
 echo $QEMU $qemu_args -m 512 -kernel $builddir/arch/x86/boot/bzImage -append \"$qemu_append $boot_args\" > $resdir/qemu-cmd
-if test -n "$RCU_BUILDONLY"
+if test -n "$TORTURE_BUILDONLY"
 then
 	echo Build-only run specified, boot/test omitted.
 	exit 0

tools/testing/selftests/rcutorture/bin/kvm.sh +6 -3

index 08c90cba79d2..73c586f6bdf6 100644
@@ -81,7 +81,7 @@ do
 		shift
 		;;
 	--buildonly)
-		RCU_BUILDONLY=1; export RCU_BUILDONLY
+		TORTURE_BUILDONLY=1
 		;;
 	--configs)
 		checkarg --configs "(list of config files)" "$#" "$2" '^[^/]*$' '^--'

@@ -374,7 +374,7 @@ then
 	echo KVM="$KVM; export KVM"
 	echo KVPATH="$KVPATH; export KVPATH"
 	echo PATH="$PATH; export PATH"
-	echo RCU_BUILDONLY="$RCU_BUILDONLY; export RCU_BUILDONLY"
+	echo TORTURE_BUILDONLY="$TORTURE_BUILDONLY; export TORTURE_BUILDONLY"
 	echo TORTURE_INITRD="$TORTURE_INITRD; export TORTURE_INITRD"
 	echo TORTURE_KMAKE_ARG="$TORTURE_KMAKE_ARG; export TORTURE_KMAKE_ARG"
 	echo RCU_QEMU_CMD="$RCU_QEMU_CMD; export RCU_QEMU_CMD"

@@ -402,4 +402,7 @@ echo
 echo
 echo " --- `date` Test summary:"
 echo Results directory: $resdir/$ds
-kvm-recheck.sh $resdir/$ds
+if test -n "$TORTURE_BUILDONLY"
+then
+	kvm-recheck.sh $resdir/$ds
+fi

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

This commit makes the torture scripts a bit more RCU-independent.

Signed-off-by Paul E. McKenney <[email protected]>

tools/testing/selftests/rcutorture/bin/kvm.sh +0 -0

From: "Paul E. McKenney" <[email protected]>

This commit makes the torture scripts a bit more RCU-independent.

Signed-off-by Paul E. McKenney <[email protected]>

---
 tools/testing/selftests/rcutorture/bin/functions.sh | 6 +++---
 tools/testing/selftests/rcutorture/bin/kvm.sh       | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

tools/testing/selftests/rcutorture/bin/functions.sh +3 -3

index 623939cf814e..41fb52b805e4 100644
@@ -124,7 +124,7 @@ identify_qemu_append () {
 
 # identify_qemu_args qemu-cmd serial-file
 #
-# Output arguments for qemu arguments based on the RCU_QEMU_MAC
+# Output arguments for qemu arguments based on the TORTURE_QEMU_MAC
 # and TORTURE_QEMU_INTERACTIVE environment variables.
 identify_qemu_args () {
 	case "$1" in

@@ -133,9 +133,9 @@ identify_qemu_args () {
 	qemu-system-ppc64)
 		echo -enable-kvm -M pseries -cpu POWER7 -nodefaults
 		echo -device spapr-vscsi
-		if test -n "$TORTURE_QEMU_INTERACTIVE" -a -n "$RCU_QEMU_MAC"
+		if test -n "$TORTURE_QEMU_INTERACTIVE" -a -n "$TORTURE_QEMU_MAC"
 		then
-			echo -device spapr-vlan,netdev=net0,mac=$RCU_QEMU_MAC
+			echo -device spapr-vlan,netdev=net0,mac=$TORTURE_QEMU_MAC
 			echo -netdev bridge,br=br0,id=net0
 		elif test -n "$TORTURE_QEMU_INTERACTIVE"
 		then

tools/testing/selftests/rcutorture/bin/kvm.sh +0 -0

index 2f9605ed5b58..1a4a68c76914 100644

tools/testing/selftests/rcutorture/bin/kvm.sh +1 -1

 		shift
 		;;
 	--no-initrd)

@@ -380,7 +380,7 @@ then
 	echo RCU_QEMU_CMD="$RCU_QEMU_CMD; export RCU_QEMU_CMD"
 	echo TORTURE_QEMU_INTERACTIVE="$TORTURE_QEMU_INTERACTIVE;
 		export TORTURE_QEMU_INTERACTIVE"
-	echo RCU_QEMU_MAC="$RCU_QEMU_MAC; export RCU_QEMU_MAC"
+	echo TORTURE_QEMU_MAC="$TORTURE_QEMU_MAC; export TORTURE_QEMU_MAC"
 	echo "mkdir -p "$resdir" || :"
 	echo "mkdir $resdir/$ds"
 	cat $T/script

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

The torture tests need to set specific values for their respective Kconfig options (e.g., CONFIG_LOCK_TORTURE_TEST), and must therefore filter any conflicting definitions from the Kconfig fragment file. Unfortunately, the code in kvm-build.sh was looking only for CONFIG_RCU_TORTURE_TEST. This commit therefore handles the general case of CONFIG_[A-Z]*TORTURE_TEST.

Signed-off-by Paul E. McKenney <[email protected]>

---
 tools/testing/selftests/rcutorture/bin/kvm-build.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

tools/testing/selftests/rcutorture/bin/kvm-build.sh +0 -0

index e838c775f709..6d0b76d918f4 100755

tools/testing/selftests/rcutorture/bin/kvm-build.sh +0 -0

 cat << ___EOF___ >> $T/config
 CONFIG_INITRAMFS_SOURCE="$TORTURE_INITRD"
 CONFIG_VIRTIO_PCI=y

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

In a normal torture-test run, the script inherits its environment variables, but this does not work when producing a script that is to run later. Therefore, definitions and exports are prepended to a dryrun script but not to a script that is run immediately. This commit reconciles this by placing definitions and exports at the beginning of the script in both cases.

Signed-off-by Paul E. McKenney <[email protected]>

---
 tools/testing/selftests/rcutorture/bin/kvm.sh | 28 ++++++++++++---------------
 1 file changed, 12 insertions(+), 16 deletions(-)

tools/testing/selftests/rcutorture/bin/kvm.sh +12 -16

index 8aa62a2dccb5..93a6c5a8517d 100644
@@ -241,8 +241,19 @@ END {
 
 # Generate a script to execute the tests in appropriate batches.
 cat << ___EOF___ > $T/script
-TORTURE_SUITE="$TORTURE_SUITE"; export TORTURE_SUITE
+CONFIGFRAG="$CONFIGFRAG"; export CONFIGFRAG
+KVM="$KVM"; export KVM
+KVPATH="$KVPATH"; export KVPATH
+PATH="$PATH"; export PATH
+TORTURE_BUILDONLY="$TORTURE_BUILDONLY"; export TORTURE_BUILDONLY
 TORTURE_DEFCONFIG="$TORTURE_DEFCONFIG"; export TORTURE_DEFCONFIG
+TORTURE_INITRD="$TORTURE_INITRD"; export TORTURE_INITRD
+TORTURE_KMAKE_ARG="$TORTURE_KMAKE_ARG"; export TORTURE_KMAKE_ARG
+TORTURE_QEMU_CMD="$TORTURE_QEMU_CMD"; export TORTURE_QEMU_CMD
+TORTURE_QEMU_INTERACTIVE="$TORTURE_QEMU_INTERACTIVE";
+	export TORTURE_QEMU_INTERACTIVE
+TORTURE_QEMU_MAC="$TORTURE_QEMU_MAC"; export TORTURE_QEMU_MAC
+TORTURE_SUITE="$TORTURE_SUITE"; export TORTURE_SUITE
 if ! test -e $resdir
 then
 	mkdir -p "$resdir" || :

@@ -371,21 +382,6 @@ ___EOF___
 
 if test "$dryrun" = script
 then
-	# Dump out the script, but define the environment variables that
-	# it needs to run standalone.
-	echo CONFIGFRAG="$CONFIGFRAG; export CONFIGFRAG"
-	echo KVM="$KVM; export KVM"
-	echo KVPATH="$KVPATH; export KVPATH"
-	echo PATH="$PATH; export PATH"
-	echo TORTURE_BUILDONLY="$TORTURE_BUILDONLY; export TORTURE_BUILDONLY"
-	echo TORTURE_INITRD="$TORTURE_INITRD; export TORTURE_INITRD"
-	echo TORTURE_KMAKE_ARG="$TORTURE_KMAKE_ARG; export TORTURE_KMAKE_ARG"
-	echo TORTURE_QEMU_CMD="$TORTURE_QEMU_CMD; export TORTURE_QEMU_CMD"
-	echo TORTURE_QEMU_INTERACTIVE="$TORTURE_QEMU_INTERACTIVE;
-		export TORTURE_QEMU_INTERACTIVE"
-	echo TORTURE_QEMU_MAC="$TORTURE_QEMU_MAC; export TORTURE_QEMU_MAC"
-	echo "mkdir -p "$resdir" || :"
-	echo "mkdir $resdir/$ds"
 	cat $T/script
 	exit 0
 elif test "$dryrun" = sched

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

The srcu_torture_stats() function prints SRCU's per-CPU c[] array with an unsigned format, which means that the number one less than zero is a very large number. This commit therefore prints this array with a signed format in order to improve readability of the rcutorture output.

Signed-off-by Paul E. McKenney <[email protected]>

 kernel/rcu/rcutorture.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

kernel/rcu/rcutorture.c +1 -0

index 3845ea99ccd4..0141fcff6bb9 100644
@@ -486,15 +486,16 @@ static void srcu_torture_barrier(void)
 
 static void srcu_torture_stats(char *page)
 {
+	long c0, c1;
 	int cpu;
 	int idx = srcu_ctl.completed & 0x1;

From: "Paul E. McKenney" <[email protected]>

Currently, torture_kthread_stopping() prints only the name of the kthread that is stopping, which can be unedifying. This commit therefore adds "Stopping" to make things more evident.

Signed-off-by Paul E. McKenney <[email protected]>

 kernel/torture.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

kernel/torture.c +0 -0

index acc9afc2f26e..f329848c3eee 100644

kernel/torture.c +0 -0

 	while (!kthread_should_stop()) {
 		torture_shutdown_absorb(title);
 		schedule_timeout_uninterruptible(1);

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

The current script does record qemu diagnostics, but the user has to know where to look for them. This commit therefore puts them into the Warnings file so that kvm-recheck.sh will display them. This change is especially useful if you are in the habit of killing the qemu process when you realize that you messed something up, but then later on wonder why the process terminated early.

Signed-off-by Paul E. McKenney <[email protected]>

From: "Paul E. McKenney" <[email protected]>

Currently, the scripts hard-code arch/x86/boot/bzImage, which does not work well for other architectures. This commit therefore provides a identify_boot_image function that selects the correct bzImage location relative to the top of the Linux source tree. This commit also adds a --bootimage argument that allows selecting some other file, for example, "vmlinux".

Signed-off-by Paul E. McKenney <[email protected]>

 tools/testing/selftests/rcutorture/bin/functions.sh | 21 +++++++++++++++++++++
 .../selftests/rcutorture/bin/kvm-test-1-run.sh      | 11 +++++------
 tools/testing/selftests/rcutorture/bin/kvm.sh       |  8 ++++++++
 3 files changed, 34 insertions(+), 6 deletions(-)

tools/testing/selftests/rcutorture/bin/functions.sh +7 -0

index 6b2adb29b073..efa95867e1cc 100644
@@ -76,6 +76,27 @@ configfrag_hotplug_cpu () {
 	grep -q '^CONFIG_HOTPLUG_CPU=y$' "$1"
 }
 
+# identify_boot_image qemu-cmd
+#
+# Returns the relative path to the kernel build image.  This will be
+# arch/<arch>/boot/bzImage unless overridden with the TORTURE_BOOT_IMAGE
+# environment variable.
+identify_boot_image () {
+	if test -n "$TORTURE_BOOT_IMAGE"

tools/testing/selftests/rcutorture/bin/functions.sh +4 -0

+		esac
+	fi
+}
+
 # identify_qemu builddir
 #
 # Returns our best guess as to which qemu command is appropriate for

tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh +3 -1

index 7848227aa4c1..7a95f86cc85a 100755
@@ -94,9 +94,11 @@ fi
 # CONFIG_YENTA=n
 if kvm-build.sh $config_template $builddir $T
 then
+	QEMU="`identify_qemu $builddir/vmlinux`"
+	BOOT_IMAGE="`identify_boot_image $QEMU`"
 	cp $builddir/Make*.out $resdir
 	cp $builddir/.config $resdir
-	cp $builddir/arch/x86/boot/bzImage $resdir
+	cp $builddir/$BOOT_IMAGE $resdir
 	parse-build.sh $resdir/Make.out $title
 	if test -f $builddir.wait
 	then

tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh +2 -2

 # Generate -smp qemu argument.
 qemu_args="-nographic $qemu_args"
 cpu_count=`configNR_CPUS.sh $config_template`

@@ -151,13 +150,13 @@ boot_args="`configfrag_boot_params "$boot_args" "$config_template"`"
 # Generate kernel-version-specific boot parameters
 boot_args="`per_version_boot_params "$boot_args" $builddir/.config $seconds`"
 
-echo $QEMU $qemu_args -m 512 -kernel $builddir/arch/x86/boot/bzImage -append \"$qemu_append $boot_args\" > $resdir/qemu-cmd
+echo $QEMU $qemu_args -m 512 -kernel $builddir/$BOOT_IMAGE -append \"$qemu_append $boot_args\" > $resdir/qemu-cmd
 if test -n "$TORTURE_BUILDONLY"
 then
 	echo Build-only run specified, boot/test omitted.
 	exit 0
 fi
-$QEMU $qemu_args -m 512 -kernel $builddir/arch/x86/boot/bzImage -append "$qemu_append $boot_args"; echo $? > $resdir/qemu-retval &
+$QEMU $qemu_args -m 512 -kernel $builddir/$BOOT_IMAGE -append "$qemu_append $boot_args"; echo $? > $resdir/qemu-retval &
 qemu_pid=$!
 commandcompleted=0
 echo Monitoring qemu job at pid $qemu_pid

tools/testing/selftests/rcutorture/bin/kvm.sh +8 -0

index 9b838c372698..4eed2a4f42c7 100644
@@ -39,6 +39,7 @@ dryrun=""
 KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
 PATH=${KVM}/bin:$PATH; export PATH
 TORTURE_DEFCONFIG=defconfig
+TORTURE_BOOT_IMAGE=""
 TORTURE_INITRD="$KVM/initrd"; export TORTURE_INITRD
 TORTURE_KMAKE_ARG=""
 TORTURE_SUITE=rcu

@@ -53,6 +54,7 @@ kversion=""
 usage () {
 	echo "Usage: $scriptname optional arguments:"
 	echo "       --bootargs kernel-boot-arguments"
+	echo "       --bootimage relative-path-to-kernel-boot-image"
 	echo "       --buildonly"
 	echo "       --configs \"config-file list\""
 	echo "       --cpus N"

@@ -80,6 +82,11 @@ do
 		TORTURE_BOOTARGS="$2"
 		shift
 		;;
+	--bootimage)
+		checkarg --bootimage "(relative path to kernel boot image)" "$#" "$2" '[a-zA-Z0-9][a-zA-Z0-9_]*' '^--'
+		TORTURE_BOOT_IMAGE="$2"
+		shift
+		;;
 	--buildonly)
 		TORTURE_BUILDONLY=1
 		;;

@@ -245,6 +252,7 @@ CONFIGFRAG="$CONFIGFRAG"; export CONFIGFRAG
 KVM="$KVM"; export KVM
 KVPATH="$KVPATH"; export KVPATH
 PATH="$PATH"; export PATH
+TORTURE_BOOT_IMAGE="$TORTURE_BOOT_IMAGE"; export TORTURE_BOOT_IMAGE
 TORTURE_BUILDONLY="$TORTURE_BUILDONLY"; export TORTURE_BUILDONLY
 TORTURE_DEFCONFIG="$TORTURE_DEFCONFIG"; export TORTURE_DEFCONFIG
 TORTURE_INITRD="$TORTURE_INITRD"; export TORTURE_INITRD

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

This commit allows rcutorture to print additional state for the RCU grace-period kthreads in cases where RCU seems reluctant to start a new grace period.

Signed-off-by Paul E. McKenney <[email protected]>

 include/linux/rcutiny.h |  4 ++++
 include/linux/rcutree.h |  1 +
 kernel/rcu/rcutorture.c |  1 +
 kernel/rcu/tree.c       | 17 +++++++++++++++++
 kernel/rcu/tree.h       |  8 +++++++-
 5 files changed, 30 insertions(+), 1 deletion(-)

include/linux/rcutiny.h +4 -0

index 425c659d54e5..d40a6a451330 100644
@@ -119,6 +119,10 @@ static inline void rcu_sched_force_quiescent_state(void)
 {
 }
 
+static inline void show_rcu_gp_kthreads(void)
+{
+}
+
 static inline void rcu_cpu_stall_reset(void)
 {
 }

include/linux/rcutree.h +1 -0

index a59ca05fd4e3..3e2f5d432743 100644
@@ -84,6 +84,7 @@ extern unsigned long rcutorture_vernum;
 long rcu_batches_completed(void);
 long rcu_batches_completed_bh(void);
 long rcu_batches_completed_sched(void);
+void show_rcu_gp_kthreads(void);
 
 void rcu_force_quiescent_state(void);
 void rcu_bh_force_quiescent_state(void);

kernel/rcu/rcutorture.c +1 -0

index 50c26a7b6d97..15af04177e7e 100644
@@ -1033,6 +1033,7 @@ rcu_torture_printk(char *page)
 				"??? Writer stall state %d g%lu c%lu f%#x\n",
 				rcu_torture_writer_state,
 				gpnum, completed, flags);
+		show_rcu_gp_kthreads();
 		rcutorture_trace_dump();
 	}
 	rtcv_snap = rcu_torture_current_version;

kernel/rcu/tree.c +17 -0

index 032106df7391..3107bd935b2b 100644
@@ -280,6 +280,21 @@ void rcu_bh_force_quiescent_state(void)
 EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state);
 
 /*
+ * Show the state of the grace-period kthreads.
+ */
+void show_rcu_gp_kthreads(void)
+{
+	struct rcu_state *rsp;
+
+	for_each_rcu_flavor(rsp) {
+		pr_info("%s: wait state: %d ->state: %#lx\n",
+			rsp->name, rsp->gp_state, rsp->gp_kthread->state);
+		/* sched_show_task(rsp->gp_kthread); */
+	}
+}
+EXPORT_SYMBOL_GPL(show_rcu_gp_kthreads);
+
+/*
  * Record the number of times rcutorture tests have been initiated and
  * terminated.  This information allows the debugfs tracing stats to be
  * correlated to the rcutorture messages, even when the rcutorture module

@@ -1611,6 +1626,7 @@ static int __noreturn rcu_gp_kthread(void *arg)
 			trace_rcu_grace_period(rsp->name,
 					       ACCESS_ONCE(rsp->gpnum),
 					       TPS("reqwait"));
+			rsp->gp_state = RCU_GP_WAIT_GPS;
 			wait_event_interruptible(rsp->gp_wq,
 						 ACCESS_ONCE(rsp->gp_flags) &
 						 RCU_GP_FLAG_INIT);

@@ -1638,6 +1654,7 @@ static int __noreturn rcu_gp_kthread(void *arg)
 			trace_rcu_grace_period(rsp->name,
 					       ACCESS_ONCE(rsp->gpnum),
 					       TPS("fqswait"));
+			rsp->gp_state = RCU_GP_WAIT_FQS;
 			ret = wait_event_interruptible_timeout(rsp->gp_wq,
 					((gf = ACCESS_ONCE(rsp->gp_flags)) &
 					 RCU_GP_FLAG_FQS) ||

kernel/rcu/tree.h +7 -1

index 75dc3c39a02a..c2fd1e722879 100644
@@ -406,7 +406,8 @@ struct rcu_state {
 	unsigned long completed;		/* # of last completed gp. */
 	struct task_struct *gp_kthread;		/* Task for grace periods. */
 	wait_queue_head_t gp_wq;		/* Where GP task waits. */
-	int gp_flags;				/* Commands for GP task. */
+	short gp_flags;				/* Commands for GP task. */
+	short gp_state;				/* GP kthread sleep state. */
 
 	/* End of fields guarded by root rcu_node's lock. */
 

@@ -469,6 +470,11 @@ struct rcu_state {
 #define RCU_GP_FLAG_INIT 0x1	/* Need grace-period initialization. */
 #define RCU_GP_FLAG_FQS  0x2	/* Need grace-period quiescent-state forcing. */
 
+/* Values for rcu_state structure's gp_flags field. */
+#define RCU_GP_WAIT_INIT 0	/* Initial state. */
+#define RCU_GP_WAIT_GPS  1	/* Wait for grace-period start. */
+#define RCU_GP_WAIT_FQS  2	/* Wait for force-quiescent-state time. */
+
 extern struct list_head rcu_struct_flavors;
 
 /* Sequence through rcu_state structures for each RCU flavor. */

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

The reaction of kvm-recheck.sh is obscure at best, and easy to miss completely. This commit therefore prints "BUG: Build failed" in the summary at the end of a run.

Signed-off-by Paul E. McKenney <[email protected]>

---
 .../selftests/rcutorture/bin/kvm-recheck-lock.sh   |  2 +-
 .../selftests/rcutorture/bin/kvm-recheck-rcu.sh    |  2 +-
 .../selftests/rcutorture/bin/kvm-recheck.sh        | 24 ++++++++++++++++------
 .../selftests/rcutorture/bin/kvm-test-1-run.sh     |  1 +
 4 files changed, 21 insertions(+), 8 deletions(-)

tools/testing/selftests/rcutorture/bin/kvm-recheck-lock.sh +1 -1

index 829186e19eb1..7f1ff1a8fc4b 100755
@@ -35,7 +35,7 @@ configfile=`echo $i | sed -e 's/^.*\///'`
 ncs=`grep "Writes:  Total:" $i/console.log 2> /dev/null | tail -1 | sed -e 's/^.* Total: //' -e 's/ .*$//'`
 if test -z "$ncs"
 then
-	echo $configfile
+	echo "$configfile -------"
 else
 	title="$configfile ------- $ncs acquisitions/releases"
 	dur=`sed -e 's/^.* locktorture.shutdown_secs=//' -e 's/ .*$//' < $i/qemu-cmd 2> /dev/null`

tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh +1 -1

index d75b1dc5ae53..307c4b95f325 100755
@@ -35,7 +35,7 @@ configfile=`echo $i | sed -e 's/^.*\///'`
 ngps=`grep ver: $i/console.log 2> /dev/null | tail -1 | sed -e 's/^.* ver: //' -e 's/ .*$//'`
 if test -z "$ngps"
 then
-	echo $configfile
+	echo "$configfile -------"
 else
 	title="$configfile ------- $ngps grace periods"
 	dur=`sed -e 's/^.* rcutorture.shutdown_secs=//' -e 's/ .*$//' < $i/qemu-cmd 2> /dev/null`

tools/testing/selftests/rcutorture/bin/kvm-recheck.sh +18 -6

index 26d78b7eaccf..ee1f6cae3d70 100755
@@ -25,6 +25,7 @@
 # Authors: Paul E. McKenney <[email protected]>
 
 PATH=`pwd`/tools/testing/selftests/rcutorture/bin:$PATH; export PATH
+. tools/testing/selftests/rcutorture/bin/functions.sh
 for rd in "$@"
 do
 	firsttime=1

@@ -39,13 +40,24 @@ do
 		fi
 		TORTURE_SUITE="`cat $i/../TORTURE_SUITE`"
 		kvm-recheck-${TORTURE_SUITE}.sh $i
-		configcheck.sh $i/.config $i/ConfigFragment
-		parse-build.sh $i/Make.out $configfile
-		parse-torture.sh $i/console.log $configfile
-		parse-console.sh $i/console.log $configfile
-		if test -r $i/Warnings
+		if test -f "$i/console.log"
 		then
-			cat $i/Warnings
+			configcheck.sh $i/.config $i/ConfigFragment
+			parse-build.sh $i/Make.out $configfile
+			parse-torture.sh $i/console.log $configfile
+			parse-console.sh $i/console.log $configfile
+			if test -r $i/Warnings
+			then
+				cat $i/Warnings
+			fi
+		else
+			if test -f "$i/qemu-cmd"
+			then
+				print_bug qemu failed
+			else
+				print_bug Build failed
+			fi
+			echo "   $i"
 		fi
 	done
 done

tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh +1 -0

index 7a95f86cc85a..51c34a91a375 100755
@@ -106,6 +106,7 @@ then
 	fi
 else
 	cp $builddir/Make*.out $resdir
+	cp $builddir/.config $resdir || :
 	echo Build failed, not running KVM, see $resdir.
 	if test -f $builddir.wait
 	then

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

The current scripting only keeps track of the git SHA-1 of the current HEAD. This can cause confusion in cases where testing ran in a git tree where changes had not yet been checked in. This commit therefore also records the output of "git diff HEAD" to provide the information needed to reconstruct the source tree that was tested.

Signed-off-by Paul E. McKenney <[email protected]>

---
 tools/testing/selftests/rcutorture/bin/kvm.sh | 5 +++++
 1 file changed, 5 insertions(+)

tools/testing/selftests/rcutorture/bin/kvm.sh +0 -0

index 4eed2a4f42c7..91661845fdec 100644

tools/testing/selftests/rcutorture/bin/kvm.sh +3 -0

+	then
+		cp $T/git-diff $resdir/$ds
+	fi
 fi
 ___EOF___
 awk < $T/cfgcpu.pack \

Signature · 1 line

1.8.1.5

From: "Paul E. McKenney" <[email protected]>

Currently, qemu runs in the foreground, which prevents the script from killing it in case the kernel locks up. This commit therefore places qemu into the background, allowing the script to recover from lockups.

Signed-off-by Paul E. McKenney <[email protected]>

 tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh +1 -1

index b1e85b049075..67e89f06e77f 100755
@@ -157,7 +157,7 @@ then
 	echo Build-only run specified, boot/test omitted.
 	exit 0
 fi
-$QEMU $qemu_args -m 512 -kernel $builddir/$BOOT_IMAGE -append "$qemu_append $boot_args"; echo $? > $resdir/qemu-retval &
+( $QEMU $qemu_args -m 512 -kernel $builddir/$BOOT_IMAGE -append "$qemu_append $boot_args"; echo $? > $resdir/qemu-retval ) &
 qemu_pid=$!
 commandcompleted=0
 echo Monitoring qemu job at pid $qemu_pid

Signature · 1 line

1.8.1.5

Hello!

This series provides torture-test updates:

1. Add forward-progress checking to distinguish between stalls in
the RCU implementation and in the torture test itself.

2. Remove the --builddir and --relbuilddir options, which have been
obsoleted by the parallel testing facility.

3. Make "--dryrun sched" output more readable by clearly indicating
where each batch of concurrent runs starts.

4. Make torture-test errors less RCU-specific. ("Hey, why did
my locktorture run complain about RCU???")

5,8-14. Rename variables to reflect the new RCU-independence of a number
of the torture-test scripts.

6. Reduce locktorture sleeping to increase intensity.

7. Add a --defconfig argument to allow other default configs to
be specified.

15. Make config-fragment filtering RCU-independent.

16. Mark private functions as static in kernel/rcu/torture.c,
courtesy of Rashika Kheria.

17-18. Make the output of "--dryrun script" independently runnable.

19. Print negative numbers when SRCU counters wrap instead of
huge 64-bit integers.

20. Fix "Stopping" torture messages.

21. Report any diagnostics issued by qemu.

22. Make kthreads spin during the last jiffy of a stutter period
to increase the intensity of torture stop-start events.

23. Permit multiple qemu and boot arguments to be specified on
the command line.

24. Choose bzImage location based on architecture.

25. Add tracing-enabled variant of TREE02 to aid debugging.

26. Dump the ftrace buffer when the RCU grace period stalls.

27. Export the RCU grace-period kthread wait state to rcutorture
to ease diagnosis of RCU grace-period stalls.

28. Fix bug in raw_cpu_inc_return().

29. Make cond_resched() report RCU quiescent states.

30. Make rcu_torture_reader() use cond_resched() instead of
unconditionally invoking schedule().

31. Complain if an all-zero cpumask is specified during a torture
shuffle operation, courtesy of Iulia Manda.

32. Make build failures more evident.

33. Capture and report the torture_create_kthread() return value when
creating the rcu_torture_fqs kthread.

34. Use elapsed time to detect hangs rather than counting "sleep 1"
commands.

35. Rearrange config fragments to ensure that RCU-sched primitives are
tested in TREE_PREEMPT_RCU kernels.

36. Add rcutorture tests for get_state_synchronize_rcu() and
cond_synchronize_rcu().

37. Add explicit tests for synchronous grace-period primitives.

38. Add missing destroy_timer_on_stack(), courtesy of Thomas Gleixner.

39. Make scripts record "git diff HEAD" to ease reproduction of
an unexpected torture-test result.

40. Run rcu_torture_writer() at normal priority.

41. Put the qemu process into the background to better handle
kernel hangs.

42. Remove reference to a non-existent Kconfig parameter.

43. Refuse to run multiple concurrent torture tests.

44. Remove __init from torture_init_begin() and torture_init_end()
to allow rcutorture to once again work as a loadable module.

45. Remove unused torture_parm() macro.

Quoted 8 lines · Paul E. McKenney

From: "Paul E. McKenney" <[email protected]>

The rcutorture output currently does not distinguish between stalls in the RCU implementation and stalls in the rcu_torture_writer() kthreads. This commit therefore adds some diagnostics to help distinguish between these two conditions, at least for the non-SRCU implementations. (SRCU does not provide evidence of update-side forward progress by design.)

Quoted 1 line

Signed-off-by Paul E. McKenney <[email protected]>

The concept makes sense, and the writer state annotations seem like a useful debugging mechanism, but having RCU know about RCU torture types seems fundamentally wrong. This mechanism accesses rcu_state, which is already implementation-specific, so why not just only define the function for the RCU implementations that support it, and then have a function pointer in the torture-test structure to report a stall?

- Josh Triplett

Quoted 210 lines

 include/linux/rcupdate.h | 19 +++++++++++++++++++
 kernel/rcu/rcutorture.c  | 37 +++++++++++++++++++++++++++++++++++++
 kernel/rcu/tree.c        | 18 ++++++++++++++++++
 3 files changed, 74 insertions(+)

include/linux/rcupdate.h +19 -0

index 00a7fd61b3c6..a6c3898e141e 100644
@@ -51,7 +51,17 @@ extern int rcu_expedited; /* for sysctl */
 extern int rcutorture_runnable; /* for sysctl */
 #endif /* #ifdef CONFIG_RCU_TORTURE_TEST */
 
+enum rcutorture_type {
+	RTORT_BUSTED,
+	RTORT_RCU,
+	RTORT_RCU_BH,
+	RTORT_RCU_SCHED,
+	RTORT_SRCU
+};
+
 #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
+void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
+			    unsigned long *gpnum, unsigned long *completed);
 void rcutorture_record_test_transition(void);
 void rcutorture_record_progress(unsigned long vernum);
 void do_trace_rcu_torture_read(const char *rcutorturename,

@@ -60,6 +70,15 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
 			       unsigned long c_old,
 			       unsigned long c);
 #else
+static inline void rcutorture_get_gp_data(enum rcutorture_type test_type,
+					  int *flags,
+					  unsigned long *gpnum,
+					  unsigned long *completed)
+{
+	*flags = 0;
+	*gpnum = 0;
+	*completed = 0;
+}
 static inline void rcutorture_record_test_transition(void)
 {
 }

kernel/rcu/rcutorture.c +37 -0

index bd30bc61bc05..1110db210318 100644
@@ -138,6 +138,15 @@ static long n_barrier_attempts;
 static long n_barrier_successes;
 static struct list_head rcu_torture_removed;
 
+static int rcu_torture_writer_state;
+#define RTWS_FIXED_DELAY	0
+#define RTWS_DELAY		1
+#define RTWS_REPLACE		2
+#define RTWS_DEF_FREE		3
+#define RTWS_EXP_SYNC		4
+#define RTWS_STUTTER		5
+#define RTWS_STOPPING		6
+
 #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
 #define RCUTORTURE_RUNNABLE_INIT 1
 #else

@@ -214,6 +223,7 @@ rcu_torture_free(struct rcu_torture *p)
  */
 
 struct rcu_torture_ops {
+	int ttype;
 	void (*init)(void);
 	int (*readlock)(void);
 	void (*read_delay)(struct torture_random_state *rrsp);

@@ -312,6 +322,7 @@ static void rcu_sync_torture_init(void)
 }
 
 static struct rcu_torture_ops rcu_ops = {
+	.ttype		= RTORT_RCU,
 	.init		= rcu_sync_torture_init,
 	.readlock	= rcu_torture_read_lock,
 	.read_delay	= rcu_read_delay,

@@ -355,6 +366,7 @@ static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
 }
 
 static struct rcu_torture_ops rcu_bh_ops = {
+	.ttype		= RTORT_RCU_BH,
 	.init		= rcu_sync_torture_init,
 	.readlock	= rcu_bh_torture_read_lock,
 	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */

@@ -397,6 +409,7 @@ call_rcu_busted(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
 }
 
 static struct rcu_torture_ops rcu_busted_ops = {
+	.ttype		= RTORT_BUSTED,
 	.init		= rcu_sync_torture_init,
 	.readlock	= rcu_torture_read_lock,
 	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */

@@ -492,6 +505,7 @@ static void srcu_torture_synchronize_expedited(void)
 }
 
 static struct rcu_torture_ops srcu_ops = {
+	.ttype		= RTORT_SRCU,
 	.init		= rcu_sync_torture_init,
 	.readlock	= srcu_torture_read_lock,
 	.read_delay	= srcu_read_delay,

@@ -527,6 +541,7 @@ static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
 }
 
 static struct rcu_torture_ops sched_ops = {
+	.ttype		= RTORT_RCU_SCHED,
 	.init		= rcu_sync_torture_init,
 	.readlock	= sched_torture_read_lock,
 	.read_delay	= rcu_read_delay,  /* just reuse rcu's version. */

@@ -699,12 +714,15 @@ rcu_torture_writer(void *arg)
 	set_user_nice(current, MAX_NICE);
 
 	do {
+		rcu_torture_writer_state = RTWS_FIXED_DELAY;
 		schedule_timeout_uninterruptible(1);
 		rp = rcu_torture_alloc();
 		if (rp == NULL)
 			continue;
 		rp->rtort_pipe_count = 0;
+		rcu_torture_writer_state = RTWS_DELAY;
 		udelay(torture_random(&rand) & 0x3ff);
+		rcu_torture_writer_state = RTWS_REPLACE;
 		old_rp = rcu_dereference_check(rcu_torture_current,
 					       current == writer_task);
 		rp->rtort_mbtest = 1;

@@ -721,8 +739,10 @@ rcu_torture_writer(void *arg)
 			else
 				exp = gp_exp;
 			if (!exp) {
+				rcu_torture_writer_state = RTWS_DEF_FREE;
 				cur_ops->deferred_free(old_rp);
 			} else {
+				rcu_torture_writer_state = RTWS_EXP_SYNC;
 				cur_ops->exp_sync();
 				list_add(&old_rp->rtort_free,
 					 &rcu_torture_removed);

@@ -743,8 +763,10 @@ rcu_torture_writer(void *arg)
 			}
 		}
 		rcutorture_record_progress(++rcu_torture_current_version);
+		rcu_torture_writer_state = RTWS_STUTTER;
 		stutter_wait("rcu_torture_writer");
 	} while (!torture_must_stop());
+	rcu_torture_writer_state = RTWS_STOPPING;
 	torture_kthread_stopping("rcu_torture_writer");
 	return 0;
 }

@@ -937,6 +959,7 @@ rcu_torture_printk(char *page)
 	int i;
 	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
 	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
+	static unsigned long rtcv_snap = ULONG_MAX;
 
 	for_each_possible_cpu(cpu) {
 		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {

@@ -997,6 +1020,20 @@ rcu_torture_printk(char *page)
 	page += sprintf(page, "\n");
 	if (cur_ops->stats)
 		cur_ops->stats(page);
+	if (rtcv_snap == rcu_torture_current_version &&
+	    rcu_torture_current != NULL) {
+		int __maybe_unused flags;
+		unsigned long __maybe_unused gpnum;
+		unsigned long __maybe_unused completed;
+
+		rcutorture_get_gp_data(cur_ops->ttype,
+				       &flags, &gpnum, &completed);
+		page += sprintf(page,
+				"??? Writer stall state %d g%lu c%lu f%#x\n",
+				rcu_torture_writer_state,
+				gpnum, completed, flags);
+	}
+	rtcv_snap = rcu_torture_current_version;
 }
 
 /*

kernel/rcu/tree.c +18 -0

index 0c47e300210a..032106df7391 100644
@@ -294,6 +294,24 @@ void rcutorture_record_test_transition(void)
 EXPORT_SYMBOL_GPL(rcutorture_record_test_transition);
 
 /*
+ * Send along grace-period-related data for rcutorture diagnostics.
+ */
+void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
+			    unsigned long *gpnum, unsigned long *completed)
+{
+	if (test_type == RTORT_SRCU || test_type == RTORT_BUSTED) {
+		*flags = 0;
+		*gpnum = 0;
+		*completed = 0;
+		return;
+	}
+	*flags = ACCESS_ONCE(rcu_state->gp_flags);
+	*gpnum = ACCESS_ONCE(rcu_state->gpnum);
+	*completed = ACCESS_ONCE(rcu_state->completed);
+}
+EXPORT_SYMBOL_GPL(rcutorture_get_gp_data);
+
+/*
  * Record the number of writer passes through the current rcutorture test.
  * This is also used to correlate debugfs tracing stats with the rcutorture
  * messages.

Signature · 1 line

1.8.1.5