From 11a1ac206d0806b0db39712c3292f6006e77a7e8 Mon Sep 17 00:00:00 2001 From: Alfredo Alvarez Fernandez Date: Fri, 19 Feb 2016 07:48:52 +0100 Subject: [PATCH] tools/lib/lockdep: Add tests for AA and ABBA locking 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 Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Sasha Levin Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1455864533-7536-3-git-send-email-alfredoalvarezernandez@gmail.com Signed-off-by: Ingo Molnar --- tools/lib/lockdep/tests/AA.c | 8 ++--- tools/lib/lockdep/tests/ABA.c | 13 +++++++ tools/lib/lockdep/tests/ABBA_2threads.c | 46 +++++++++++++++++++++++++ 3 files changed, 63 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 0f782ff404ac..18211a5f354f 100644 --- a/tools/lib/lockdep/tests/AA.c +++ b/tools/lib/lockdep/tests/AA.c @@ -1,13 +1,13 @@ #include -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 000000000000..0f782ff404ac --- /dev/null +++ b/tools/lib/lockdep/tests/ABA.c @@ -0,0 +1,13 @@ +#include + +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 000000000000..cd807d736361 --- /dev/null +++ b/tools/lib/lockdep/tests/ABBA_2threads.c @@ -0,0 +1,46 @@ +#include +#include + +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; +} -- 2.20.1