linux-kernel - [PATCH v2 11/17] locking/lockdep: Adjust lockdep selftest cases

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Date:   Thu, 16 May 2019 16:00:09 +0800
From:   Yuyang Du <duyuyang@...il.com>
To:     peterz@...radead.org, will.deacon@....com, mingo@...nel.org
Cc:     bvanassche@....org, ming.lei@...hat.com, frederic@...nel.org,
        tglx@...utronix.de, boqun.feng@...il.com, paulmck@...ux.ibm.com,
        linux-kernel@...r.kernel.org, Yuyang Du <duyuyang@...il.com>
Subject: [PATCH v2 11/17] locking/lockdep: Adjust lockdep selftest cases

With read-write lock support, some read-write lock cases need to be updated,
specifically, some read-lock involved deadlocks are actually not deadlocks.
Hope I am not wildly wrong.

Signed-off-by: Yuyang Du <duyuyang@...il.com>
---
 lib/locking-selftest.c | 44 +++++++++++++++++++++++++++++++++-----------
 1 file changed, 33 insertions(+), 11 deletions(-)

diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index a170554..f83f047 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -424,7 +424,7 @@ static void rwsem_ABBA2(void)
 	ML(Y1);
 	RSL(X1);
 	RSU(X1);
-	MU(Y1); // should fail
+	MU(Y1); // should NOT fail
 }
 
 
@@ -462,12 +462,13 @@ static void rwsem_ABBA3(void)
 
 /*
  * ABBA deadlock:
+ *
+ * Should fail except for either A or B is read lock.
  */
-
 #define E()					\
 						\
 	LOCK_UNLOCK_2(A, B);			\
-	LOCK_UNLOCK_2(B, A); /* fail */
+	LOCK_UNLOCK_2(B, A);
 
 /*
  * 6 testcases:
@@ -494,13 +495,15 @@ static void rwsem_ABBA3(void)
 
 /*
  * AB BC CA deadlock:
+ *
+ * Should fail except for read or recursive-read locks.
  */
 
 #define E()					\
 						\
 	LOCK_UNLOCK_2(A, B);			\
 	LOCK_UNLOCK_2(B, C);			\
-	LOCK_UNLOCK_2(C, A); /* fail */
+	LOCK_UNLOCK_2(C, A);
 
 /*
  * 6 testcases:
@@ -527,13 +530,15 @@ static void rwsem_ABBA3(void)
 
 /*
  * AB CA BC deadlock:
+ *
+ * Should fail except for read or recursive-read locks.
  */
 
 #define E()					\
 						\
 	LOCK_UNLOCK_2(A, B);			\
 	LOCK_UNLOCK_2(C, A);			\
-	LOCK_UNLOCK_2(B, C); /* fail */
+	LOCK_UNLOCK_2(B, C);
 
 /*
  * 6 testcases:
@@ -560,6 +565,8 @@ static void rwsem_ABBA3(void)
 
 /*
  * AB BC CD DA deadlock:
+ *
+ * Should fail except for read or recursive-read locks.
  */
 
 #define E()					\
@@ -567,7 +574,7 @@ static void rwsem_ABBA3(void)
 	LOCK_UNLOCK_2(A, B);			\
 	LOCK_UNLOCK_2(B, C);			\
 	LOCK_UNLOCK_2(C, D);			\
-	LOCK_UNLOCK_2(D, A); /* fail */
+	LOCK_UNLOCK_2(D, A);
 
 /*
  * 6 testcases:
@@ -594,13 +601,15 @@ static void rwsem_ABBA3(void)
 
 /*
  * AB CD BD DA deadlock:
+ *
+ * Should fail except for read or recursive-read locks.
  */
 #define E()					\
 						\
 	LOCK_UNLOCK_2(A, B);			\
 	LOCK_UNLOCK_2(C, D);			\
 	LOCK_UNLOCK_2(B, D);			\
-	LOCK_UNLOCK_2(D, A); /* fail */
+	LOCK_UNLOCK_2(D, A);
 
 /*
  * 6 testcases:
@@ -627,13 +636,15 @@ static void rwsem_ABBA3(void)
 
 /*
  * AB CD BC DA deadlock:
+ *
+ * Should fail except for read or recursive-read locks.
  */
 #define E()					\
 						\
 	LOCK_UNLOCK_2(A, B);			\
 	LOCK_UNLOCK_2(C, D);			\
 	LOCK_UNLOCK_2(B, C);			\
-	LOCK_UNLOCK_2(D, A); /* fail */
+	LOCK_UNLOCK_2(D, A);
 
 /*
  * 6 testcases:
@@ -1238,7 +1249,7 @@ static inline void print_testname(const char *testname)
 /*
  * 'read' variant: rlocks must not trigger.
  */
-#define DO_TESTCASE_6R(desc, name)				\
+#define DO_TESTCASE_6AA(desc, name)				\
 	print_testname(desc);					\
 	dotest(name##_spin, FAILURE, LOCKTYPE_SPIN);		\
 	dotest(name##_wlock, FAILURE, LOCKTYPE_RWLOCK);		\
@@ -1249,6 +1260,17 @@ static inline void print_testname(const char *testname)
 	dotest_rt(name##_rtmutex, FAILURE, LOCKTYPE_RTMUTEX);	\
 	pr_cont("\n");
 
+#define DO_TESTCASE_6R(desc, name)				\
+	print_testname(desc);					\
+	dotest(name##_spin, FAILURE, LOCKTYPE_SPIN);		\
+	dotest(name##_wlock, FAILURE, LOCKTYPE_RWLOCK);		\
+	dotest(name##_rlock, SUCCESS, LOCKTYPE_RWLOCK);		\
+	dotest(name##_mutex, FAILURE, LOCKTYPE_MUTEX);		\
+	dotest(name##_wsem, FAILURE, LOCKTYPE_RWSEM);		\
+	dotest(name##_rsem, SUCCESS, LOCKTYPE_RWSEM);		\
+	dotest_rt(name##_rtmutex, FAILURE, LOCKTYPE_RTMUTEX);	\
+	pr_cont("\n");
+
 #define DO_TESTCASE_2I(desc, name, nr)				\
 	DO_TESTCASE_1("hard-"desc, name##_hard, nr);		\
 	DO_TESTCASE_1("soft-"desc, name##_soft, nr);
@@ -1991,7 +2013,7 @@ void locking_selftest(void)
 	debug_locks_silent = !debug_locks_verbose;
 	lockdep_set_selftest_task(current);
 
-	DO_TESTCASE_6R("A-A deadlock", AA);
+	DO_TESTCASE_6AA("A-A deadlock", AA);
 	DO_TESTCASE_6R("A-B-B-A deadlock", ABBA);
 	DO_TESTCASE_6R("A-B-B-C-C-A deadlock", ABBCCA);
 	DO_TESTCASE_6R("A-B-C-A-B-C deadlock", ABCABC);
@@ -2048,7 +2070,7 @@ void locking_selftest(void)
 	pr_cont("             |");
 	dotest(rlock_ABBA2, SUCCESS, LOCKTYPE_RWLOCK);
 	pr_cont("             |");
-	dotest(rwsem_ABBA2, FAILURE, LOCKTYPE_RWSEM);
+	dotest(rwsem_ABBA2, SUCCESS, LOCKTYPE_RWSEM);
 
 	print_testname("mixed write-lock/lock-write ABBA");
 	pr_cont("             |");
-- 
1.8.3.1