[PATCH rcu 0/4] RCU/lock torture updates for v6.8

[PATCH rcu 0/4] RCU/lock torture updates for v6.8

[Neeraj Upadhyay (AMD)]

Hello,

This series contains torture-test updates:

1.      Increase Hamming distance between call_rcu_chain and
        rcu_call_chains.

2.      add nolibc init support for mips, ppc and rv64, courtesy of
        Thomas Weißschuh.

3.      Add mid-sized stall to TREE07.

4.      Add fqs_holdoff check before fqs_task is created, courtesy
        of Zqiang.


Thanks
Neeraj

------------------------------------------------------------------------

 kernel/locking/locktorture.c                               |   18 +++++++++---------
 kernel/rcu/rcutorture.c                                    |    4 +++-
 tools/testing/selftests/rcutorture/bin/mkinitrd.sh         |    5 ++++-
 tools/testing/selftests/rcutorture/configs/rcu/TREE07.boot |    3 +++
 4 files changed, 19 insertions(+), 11 deletions(-)

[PATCH rcu 1/4] locktorture: Increase Hamming distance between call_rcu_chain and rcu_call_chains

[Neeraj Upadhyay (AMD)]

From: "Paul E. McKenney" <paulmck@kernel.org>

One letter difference is really not enough, so this commit changes
call_rcu_chain to call_rcu_chain_list.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
---
 kernel/locking/locktorture.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 69d3cd2cfc3b..415d81e6ce70 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -124,7 +124,7 @@ struct call_rcu_chain {
 	struct rcu_head crc_rh;
 	bool crc_stop;
 };
-struct call_rcu_chain *call_rcu_chain;
+struct call_rcu_chain *call_rcu_chain_list;
 
 /* Forward reference. */
 static void lock_torture_cleanup(void);
@@ -1074,12 +1074,12 @@ static int call_rcu_chain_init(void)
 
 	if (call_rcu_chains <= 0)
 		return 0;
-	call_rcu_chain = kcalloc(call_rcu_chains, sizeof(*call_rcu_chain), GFP_KERNEL);
-	if (!call_rcu_chain)
+	call_rcu_chain_list = kcalloc(call_rcu_chains, sizeof(*call_rcu_chain_list), GFP_KERNEL);
+	if (!call_rcu_chain_list)
 		return -ENOMEM;
 	for (i = 0; i < call_rcu_chains; i++) {
-		call_rcu_chain[i].crc_stop = false;
-		call_rcu(&call_rcu_chain[i].crc_rh, call_rcu_chain_cb);
+		call_rcu_chain_list[i].crc_stop = false;
+		call_rcu(&call_rcu_chain_list[i].crc_rh, call_rcu_chain_cb);
 	}
 	return 0;
 }
@@ -1089,13 +1089,13 @@ static void call_rcu_chain_cleanup(void)
 {
 	int i;
 
-	if (!call_rcu_chain)
+	if (!call_rcu_chain_list)
 		return;
 	for (i = 0; i < call_rcu_chains; i++)
-		smp_store_release(&call_rcu_chain[i].crc_stop, true);
+		smp_store_release(&call_rcu_chain_list[i].crc_stop, true);
 	rcu_barrier();
-	kfree(call_rcu_chain);
-	call_rcu_chain = NULL;
+	kfree(call_rcu_chain_list);
+	call_rcu_chain_list = NULL;
 }
 
 static void lock_torture_cleanup(void)
-- 
2.40.1

[PATCH rcu 2/4] rcutorture: add nolibc init support for mips, ppc and rv64

[Neeraj Upadhyay (AMD)]

From: Thomas Weißschuh <linux@weissschuh.net>

Use nolibc for all support architectures.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
---
 tools/testing/selftests/rcutorture/bin/mkinitrd.sh | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/rcutorture/bin/mkinitrd.sh b/tools/testing/selftests/rcutorture/bin/mkinitrd.sh
index 212c52ca90b5..f3f867129560 100755
--- a/tools/testing/selftests/rcutorture/bin/mkinitrd.sh
+++ b/tools/testing/selftests/rcutorture/bin/mkinitrd.sh
@@ -67,7 +67,10 @@ ___EOF___
 # build using nolibc on supported archs (smaller executable) and fall
 # back to regular glibc on other ones.
 if echo -e "#if __x86_64__||__i386__||__i486__||__i586__||__i686__" \
-	   "||__ARM_EABI__||__aarch64__||__s390x__||__loongarch__\nyes\n#endif" \
+	   "||__ARM_EABI__||__aarch64__||(__mips__ && _ABIO32)" \
+	   "||__powerpc__||(__riscv && __riscv_xlen == 64)" \
+	   "||__s390x__||__loongarch__" \
+	   "\nyes\n#endif" \
    | ${CROSS_COMPILE}gcc -E -nostdlib -xc - \
    | grep -q '^yes'; then
 	# architecture supported by nolibc
-- 
2.40.1

[PATCH rcu 3/4] rcutorture: Add mid-sized stall to TREE07

[Neeraj Upadhyay (AMD)]

From: "Paul E. McKenney" <paulmck@kernel.org>

There is code in rcu_implicit_dynticks_qs() that checks for the current
grace period being halfway to the RCU CPU stall timeout, but rcutorture
currently does not test this code.  This commit therefore adds a 14-second
stall to the TREE07 scenario in order to test this code given the default
RCU CPU stall warning timeout of 21 seconds.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
---
 tools/testing/selftests/rcutorture/configs/rcu/TREE07.boot | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE07.boot b/tools/testing/selftests/rcutorture/configs/rcu/TREE07.boot
index d44609937503..979edbf4c820 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/TREE07.boot
+++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE07.boot
@@ -1 +1,4 @@
 nohz_full=2-9
+rcutorture.stall_cpu=14
+rcutorture.stall_cpu_holdoff=90
+rcutorture.fwd_progress=0
-- 
2.40.1

[PATCH rcu 4/4] rcutorture: Add fqs_holdoff check before fqs_task is created

[Neeraj Upadhyay (AMD)]

From: Zqiang <qiang.zhang1211@gmail.com>

For rcutorture tests on RCU implementations that support
force-quiescent-state operations and that set the fqs_duration module
parameter greater than zero, the fqs_task kthread will be created.
However, if the fqs_holdoff module parameter is not set, then its default
value of zero will cause fqs_task enter a long-term busy loop until
stopped by kthread_stop().  This commit therefore adds a fqs_holdoff
check before the fqs_task is created, making sure that whenever the
fqs_task is created, the fqs_holdoff will be greater than zero.

Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
---
 kernel/rcu/rcutorture.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 30fc9d34e329..a0b2520bd32b 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -3872,7 +3872,9 @@ rcu_torture_init(void)
 	}
 	if (fqs_duration < 0)
 		fqs_duration = 0;
-	if (fqs_duration) {
+	if (fqs_holdoff < 0)
+		fqs_holdoff = 0;
+	if (fqs_duration && fqs_holdoff) {
 		/* Create the fqs thread */
 		firsterr = torture_create_kthread(rcu_torture_fqs, NULL,
 						  fqs_task);
-- 
2.40.1