[PATCH v3 28/30] locking/lockdep: Adjust selftest case for recursive read lock

Yuyang Du
2019-06-28T09:17:51Z

Now that we support recursive read locks, a previously failed case:

----------------------------------------------------------------------------
| spin |wlock |rlock |mutex | wsem | rsem |
--------------------------------------------------------------------------
mixed read-lock/lock-write ABBA: |FAILED| | ok |

can be added back. Now we have:

Good, all 262 testcases passed!

See the case in: e91498589746065e3a ("Add mixed read-write ABBA tests")

It is worth noting that previously for the lock inversion deadlock checks,
the SUCCESS's of _rlock cases are only because the dependencies having
recursive-read locks (rlock) are not included in the graph.

Signed-off-by: Yuyang Du <duyuyang@gmail.com>
---
lib/locking-selftest.c | 32 ++++++++++++++++++--------------
1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index a170554..7d14d87 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -462,12 +462,13 @@ static void rwsem_ABBA3(void)

/*
* ABBA deadlock:
+ *
+ * Should fail except for either A or B is rlock.
*/
-
#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 rlock.
*/

#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 rlock.
*/

#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 rlock.
*/

#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 rlock.
*/
#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 rlock.
*/
#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:
@@ -2033,13 +2044,6 @@ void locking_selftest(void)
print_testname("mixed read-lock/lock-write ABBA");
pr_cont(" |");
dotest(rlock_ABBA1, FAILURE, LOCKTYPE_RWLOCK);
-#ifdef CONFIG_PROVE_LOCKING
- /*
- * Lockdep does indeed fail here, but there's nothing we can do about
- * that now. Don't kill lockdep for it.
- */
- unexpected_testcase_failures--;
-#endif

pr_cont(" |");
dotest(rwsem_ABBA1, FAILURE, LOCKTYPE_RWSEM);
--
1.8.3.1