tools/lib/lockdep: Add tests for AA and ABBA locking (11a1ac20) · Commits · 戴 / test

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. These tests found a lockdep bug - fixed by the next commit. Signed-off-by:

Alfredo Alvarez Fernandez <alfredoalvarezfernandez@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1455864533-7536-3-git-send-email-alfredoalvarezernandez@gmail.com Signed-off-by:

Ingo Molnar <mingo@kernel.org>

tools/lib/lockdep/tests/AA.c

+4 −4

Original line number	Diff line number	Diff line
		#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;
		}

tools/lib/lockdep/tests/ABA.c

0 → 100644

+13 −0

Original line number	Diff line number	Diff line
		#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);
		}

tools/lib/lockdep/tests/ABBA_2threads.c

0 → 100644

+46 −0

Original line number	Diff line number	Diff line
		#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;
		}

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