linux-kernel - [PATCH 3/3] WIP: locking/lockdep: selftests: Add selftests for SRCU

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Date:   Thu, 12 Jan 2023 22:59:55 -0800
From:   Boqun Feng <boqun.feng@...il.com>
To:     linux-kernel@...r.kernel.org, rcu@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>, Will Deacon <will@...nel.org>,
        Waiman Long <longman@...hat.com>,
        Boqun Feng <boqun.feng@...il.com>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Josh Triplett <josh@...htriplett.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        David Woodhouse <dwmw2@...radead.org>,
        Paolo Bonzini <pbonzini@...hat.com>, seanjc@...gle.com,
        Joel Fernandes <joel@...lfernandes.org>,
        Matthew Wilcox <willy@...radead.org>,
        Michal Luczaj <mhal@...x.co>
Subject: [PATCH 3/3] WIP: locking/lockdep: selftests: Add selftests for SRCU

Signed-off-by: Boqun Feng <boqun.feng@...il.com>
---
 lib/locking-selftest.c | 71 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 8d24279fad05..5fc206a2f9f1 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -60,6 +60,7 @@ __setup("debug_locks_verbose=", setup_debug_locks_verbose);
 #define LOCKTYPE_RTMUTEX 0x20
 #define LOCKTYPE_LL	0x40
 #define LOCKTYPE_SPECIAL 0x80
+#define LOCKTYPE_SRCU	0x100
 
 static struct ww_acquire_ctx t, t2;
 static struct ww_mutex o, o2, o3;
@@ -100,6 +101,13 @@ static DEFINE_RT_MUTEX(rtmutex_D);
 
 #endif
 
+#ifdef CONFIG_SRCU
+static struct lock_class_key srcu_A_key;
+static struct lock_class_key srcu_B_key;
+static struct srcu_struct srcu_A;
+static struct srcu_struct srcu_B;
+#endif
+
 /*
  * Locks that we initialize dynamically as well so that
  * e.g. X1 and X2 becomes two instances of the same class,
@@ -1418,6 +1426,12 @@ static void reset_locks(void)
 	memset(&ww_lockdep.acquire_key, 0, sizeof(ww_lockdep.acquire_key));
 	memset(&ww_lockdep.mutex_key, 0, sizeof(ww_lockdep.mutex_key));
 	local_irq_enable();
+
+#ifdef CONFIG_SRCU
+	__init_srcu_struct(&srcu_A, "srcuA", &srcu_A_key);
+	__init_srcu_struct(&srcu_B, "srcuB", &srcu_B_key);
+#endif
+
 }
 
 #undef I
@@ -2360,6 +2374,58 @@ static void ww_tests(void)
 	pr_cont("\n");
 }
 
+static void srcu_ABBA(void)
+{
+	int ia, ib;
+
+	ia = srcu_read_lock(&srcu_A);
+	synchronize_srcu(&srcu_B);
+	srcu_read_unlock(&srcu_A, ia);
+
+	ib = srcu_read_lock(&srcu_B);
+	synchronize_srcu(&srcu_A);
+	srcu_read_unlock(&srcu_B, ib); // should fail
+}
+
+static void srcu_mutex_ABBA(void)
+{
+	int ia;
+
+	mutex_lock(&mutex_A);
+	synchronize_srcu(&srcu_A);
+	mutex_unlock(&mutex_A);
+
+	ia = srcu_read_lock(&srcu_A);
+	mutex_lock(&mutex_A);
+	mutex_unlock(&mutex_A);
+	srcu_read_unlock(&srcu_A, ia); // should fail
+}
+
+static void srcu_irqsafe(void)
+{
+	int ia;
+
+	HARDIRQ_ENTER();
+	ia = srcu_read_lock(&srcu_A);
+	srcu_read_unlock(&srcu_A, ia);
+	HARDIRQ_EXIT();
+
+	synchronize_srcu(&srcu_A); // should NOT fail
+}
+
+static void srcu_tests(void)
+{
+	printk("  --------------------------------------------------------------------------\n");
+	printk("  | SRCU tests |\n");
+	printk("  ---------------\n");
+	print_testname("ABBA read-sync/read-sync");
+	dotest(srcu_ABBA, FAILURE, LOCKTYPE_SRCU);
+	print_testname("ABBA mutex-sync/read-mutex");
+	dotest(srcu_mutex_ABBA, FAILURE, LOCKTYPE_SRCU);
+	print_testname("Irqsafe synchronize_srcu");
+	dotest(srcu_irqsafe, SUCCESS, LOCKTYPE_SRCU);
+	pr_cont("\n");
+}
 
 /*
  * <in hardirq handler>
@@ -2881,6 +2947,10 @@ void locking_selftest(void)
 	printk("  --------------------------------------------------------------------------\n");
 
 	init_shared_classes();
+#ifdef CONFIG_SRCU
+	__init_srcu_struct(&srcu_A, "srcuA", &srcu_A_key);
+	__init_srcu_struct(&srcu_B, "srcuB", &srcu_B_key);
+#endif
 	lockdep_set_selftest_task(current);
 
 	DO_TESTCASE_6R("A-A deadlock", AA);
@@ -2965,6 +3035,7 @@ void locking_selftest(void)
 	DO_TESTCASE_6x2x2RW("irq read-recursion #3", irq_read_recursion3);
 
 	ww_tests();
+	srcu_tests();
 
 	force_read_lock_recursive = 0;
 	/*
-- 
2.38.1