[PATCH rcu 1/4] rcutorture: Make rcutorture support srcu double call test

From: Paul E. McKenney
Date: Tue Jun 04 2024 - 18:37:15 EST


From: Zqiang <qiang.zhang1211@xxxxxxxxx>

This commit allows rcutorture to test double-call_srcu() when the
CONFIG_DEBUG_OBJECTS_RCU_HEAD Kconfig option is enabled. The non-raw
sdp structure's ->spinlock will be acquired in call_srcu(), hence this
commit also removes the current IRQ and preemption disabling so as to
avoid lockdep complaints.

Link: https://lore.kernel.org/all/20240407112714.24460-1-qiang.zhang1211@xxxxxxxxx/

Signed-off-by: Zqiang <qiang.zhang1211@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
kernel/rcu/rcutorture.c | 46 +++++++++++++++++++++++------------------
1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 807fbf6123a77..44cc455e1b615 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -390,6 +390,7 @@ struct rcu_torture_ops {
int extendables;
int slow_gps;
int no_pi_lock;
+ int debug_objects;
const char *name;
};

@@ -577,6 +578,7 @@ static struct rcu_torture_ops rcu_ops = {
.irq_capable = 1,
.can_boost = IS_ENABLED(CONFIG_RCU_BOOST),
.extendables = RCUTORTURE_MAX_EXTEND,
+ .debug_objects = 1,
.name = "rcu"
};

@@ -747,6 +749,7 @@ static struct rcu_torture_ops srcu_ops = {
.cbflood_max = 50000,
.irq_capable = 1,
.no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
+ .debug_objects = 1,
.name = "srcu"
};

@@ -786,6 +789,7 @@ static struct rcu_torture_ops srcud_ops = {
.cbflood_max = 50000,
.irq_capable = 1,
.no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
+ .debug_objects = 1,
.name = "srcud"
};

@@ -3455,7 +3459,6 @@ rcu_torture_cleanup(void)
cur_ops->gp_slow_unregister(NULL);
}

-#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
static void rcu_torture_leak_cb(struct rcu_head *rhp)
{
}
@@ -3473,7 +3476,6 @@ static void rcu_torture_err_cb(struct rcu_head *rhp)
*/
pr_alert("%s: duplicated callback was invoked.\n", KBUILD_MODNAME);
}
-#endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */

/*
* Verify that double-free causes debug-objects to complain, but only
@@ -3482,39 +3484,43 @@ static void rcu_torture_err_cb(struct rcu_head *rhp)
*/
static void rcu_test_debug_objects(void)
{
-#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
struct rcu_head rh1;
struct rcu_head rh2;
+ int idx;
+
+ if (!IS_ENABLED(CONFIG_DEBUG_OBJECTS_RCU_HEAD)) {
+ pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_%s()\n",
+ KBUILD_MODNAME, cur_ops->name);
+ return;
+ }
+
+ if (WARN_ON_ONCE(cur_ops->debug_objects &&
+ (!cur_ops->call || !cur_ops->cb_barrier)))
+ return;
+
struct rcu_head *rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);

init_rcu_head_on_stack(&rh1);
init_rcu_head_on_stack(&rh2);
- pr_alert("%s: WARN: Duplicate call_rcu() test starting.\n", KBUILD_MODNAME);
+ pr_alert("%s: WARN: Duplicate call_%s() test starting.\n", KBUILD_MODNAME, cur_ops->name);

/* Try to queue the rh2 pair of callbacks for the same grace period. */
- preempt_disable(); /* Prevent preemption from interrupting test. */
- rcu_read_lock(); /* Make it impossible to finish a grace period. */
- call_rcu_hurry(&rh1, rcu_torture_leak_cb); /* Start grace period. */
- local_irq_disable(); /* Make it harder to start a new grace period. */
- call_rcu_hurry(&rh2, rcu_torture_leak_cb);
- call_rcu_hurry(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
+ idx = cur_ops->readlock(); /* Make it impossible to finish a grace period. */
+ cur_ops->call(&rh1, rcu_torture_leak_cb); /* Start grace period. */
+ cur_ops->call(&rh2, rcu_torture_leak_cb);
+ cur_ops->call(&rh2, rcu_torture_err_cb); /* Duplicate callback. */
if (rhp) {
- call_rcu_hurry(rhp, rcu_torture_leak_cb);
- call_rcu_hurry(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
+ cur_ops->call(rhp, rcu_torture_leak_cb);
+ cur_ops->call(rhp, rcu_torture_err_cb); /* Another duplicate callback. */
}
- local_irq_enable();
- rcu_read_unlock();
- preempt_enable();
+ cur_ops->readunlock(idx);

/* Wait for them all to get done so we can safely return. */
- rcu_barrier();
- pr_alert("%s: WARN: Duplicate call_rcu() test complete.\n", KBUILD_MODNAME);
+ cur_ops->cb_barrier();
+ pr_alert("%s: WARN: Duplicate call_%s() test complete.\n", KBUILD_MODNAME, cur_ops->name);
destroy_rcu_head_on_stack(&rh1);
destroy_rcu_head_on_stack(&rh2);
kfree(rhp);
-#else /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
- pr_alert("%s: !CONFIG_DEBUG_OBJECTS_RCU_HEAD, not testing duplicate call_rcu()\n", KBUILD_MODNAME);
-#endif /* #else #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
}

static void rcutorture_sync(void)
--
2.40.1