linux-kernel - [PATCH 2/3] tools/liblockdep: add tests

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Date:	Thu, 11 Feb 2016 00:33:31 +0100
From:	Alfredo Alvarez Fernandez <alfredoalvarezfernandez@...il.com>
To:	mingo@...hat.com, peterz@...radead.org, sasha.levin@...cle.com
Cc:	linux-kernel@...r.kernel.org,
	Alfredo Alvarez Fernandez <alfredoalvarezfernandez@...il.com>
Subject: [PATCH 2/3] tools/liblockdep: add tests

From: Alfredo Alvarez Fernandez <alfredoalvarezfernandez@...il.com>

Add test for AA and 2 threaded ABBA locking.

Rename AA.c to ABA.c since it was implementing an ABA instead of a pure
AA. Now both cases are covered.

The expected output for AA.c is that the process blocks and lockdep
reports a deadlock.

ABBA_2threads.c differs from ABBA.c in that lockdep keeps separate chains
of held locks per task. This can lead to different behaviour regarding
lock detection. The expected output for this test is that the process
blocks and lockdep reports a circular locking dependency.

Signed-off-by: Alfredo Alvarez Fernandez <alfredoalvarezfernandez@...il.com>
---
 tools/lib/lockdep/tests/AA.c            |  8 +++---
 tools/lib/lockdep/tests/ABA.c           | 13 ++++++++++
 tools/lib/lockdep/tests/ABBA_2threads.c | 43 +++++++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+), 4 deletions(-)
 create mode 100644 tools/lib/lockdep/tests/ABA.c
 create mode 100644 tools/lib/lockdep/tests/ABBA_2threads.c

diff --git a/tools/lib/lockdep/tests/AA.c b/tools/lib/lockdep/tests/AA.c
index 0f782ff..18211a5 100644
--- a/tools/lib/lockdep/tests/AA.c
+++ b/tools/lib/lockdep/tests/AA.c
@@ -1,13 +1,13 @@
 #include <liblockdep/mutex.h>
 
-void main(void)
+int main(void)
 {
-	pthread_mutex_t a, b;
+	pthread_mutex_t a;
 
 	pthread_mutex_init(&a, NULL);
-	pthread_mutex_init(&b, NULL);
 
 	pthread_mutex_lock(&a);
-	pthread_mutex_lock(&b);
 	pthread_mutex_lock(&a);
+
+	return 0;
 }
diff --git a/tools/lib/lockdep/tests/ABA.c b/tools/lib/lockdep/tests/ABA.c
new file mode 100644
index 0000000..0f782ff
--- /dev/null
+++ b/tools/lib/lockdep/tests/ABA.c
@@ -0,0 +1,13 @@
+#include <liblockdep/mutex.h>
+
+void main(void)
+{
+	pthread_mutex_t a, b;
+
+	pthread_mutex_init(&a, NULL);
+	pthread_mutex_init(&b, NULL);
+
+	pthread_mutex_lock(&a);
+	pthread_mutex_lock(&b);
+	pthread_mutex_lock(&a);
+}
diff --git a/tools/lib/lockdep/tests/ABBA_2threads.c b/tools/lib/lockdep/tests/ABBA_2threads.c
new file mode 100644
index 0000000..62b759c
--- /dev/null
+++ b/tools/lib/lockdep/tests/ABBA_2threads.c
@@ -0,0 +1,43 @@
+#include <stdio.h>
+#include <pthread.h>
+
+pthread_mutex_t a = PTHREAD_MUTEX_INITIALIZER;
+pthread_mutex_t b = PTHREAD_MUTEX_INITIALIZER;
+pthread_barrier_t bar;
+
+void* ba_lock(void *arg) {
+	int ret, i;
+	pthread_mutex_lock(&b);
+
+	if (pthread_barrier_wait(&bar) == PTHREAD_BARRIER_SERIAL_THREAD)
+	    pthread_barrier_destroy(&bar);
+
+	pthread_mutex_lock(&a);
+
+	pthread_mutex_unlock(&a);
+	pthread_mutex_unlock(&b);
+}
+
+int main(void)
+{
+	pthread_t t;
+	pthread_barrier_init(&bar, NULL, 2);
+
+	if (pthread_create(&t, NULL, ba_lock, NULL)) {
+		fprintf(stderr, "pthread_create() failed\n");
+		return 1;
+	}
+	pthread_mutex_lock(&a);
+
+	if (pthread_barrier_wait(&bar) == PTHREAD_BARRIER_SERIAL_THREAD)
+	    pthread_barrier_destroy(&bar);
+
+	pthread_mutex_lock(&b);
+
+	pthread_mutex_unlock(&b);
+	pthread_mutex_unlock(&a);
+
+	pthread_join(t, NULL);
+
+	return 0;
+}
-- 
2.5.0