[PATCH] lockdep/selftest: Add tests for the mixed read-write case.

From: Maarten Lankhorst
Date: Tue Mar 26 2013 - 12:15:20 EST


rlock_AA5 will pass unexpectedly, marking the test as FAILED and breaking lockdep for everyone.

The following test should make lockdep complain, but currently doesn't:

lock(a); readlock(x);

writelock(x); lock(a);

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxx>
---

diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 8a1a230..d0d2540 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -301,6 +301,51 @@ static void rsem_AA3(void)
RSL(X2); // this one should fail
}

+static void rlock_AA4(void)
+{
+ ML(A);
+ RL(X1);
+ RU(X1);
+ MU(A);
+
+ RL(X1);
+ ML(A);
+}
+
+static void rsem_AA4(void)
+{
+ ML(A);
+ RSL(X1);
+ RSU(X1);
+ MU(A);
+
+ RSL(X1);
+ ML(A);
+}
+
+static void rlock_AA5(void)
+{
+ ML(A);
+ RL(X1);
+ RU(X1);
+ MU(A);
+
+ WL(X1);
+ ML(A);
+}
+
+static void rsem_AA5(void)
+{
+ ML(A);
+ RSL(X1);
+ RSU(X1);
+ MU(A);
+
+ WSL(X1);
+ ML(A);
+}
+
+
/*
* ABBA deadlock:
*/
@@ -1661,6 +1706,21 @@ void locking_selftest(void)
dotest(rsem_AA3, FAILURE, LOCKTYPE_RWSEM);
printk("\n");

+ print_testname("mixed normal-read-lock");
+ printk(" |");
+ dotest(rlock_AA4, SUCCESS, LOCKTYPE_RWLOCK);
+ printk(" |");
+ dotest(rsem_AA4, FAILURE, LOCKTYPE_RWSEM);
+ printk("\n");
+
+ print_testname("mixed normal-r/w-lock");
+ printk(" |");
+ dotest(rlock_AA5, FAILURE, LOCKTYPE_RWLOCK);
+ printk(" |");
+ dotest(rsem_AA5, FAILURE, LOCKTYPE_RWSEM);
+ printk("\n");
+
+
printk(" --------------------------------------------------------------------------\n");

/*

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