Commit-ID: 11a1ac206d0806b0db39712c3292f6006e77a7e8 Gitweb: http://git.kernel.org/tip/11a1ac206d0806b0db39712c3292f6006e77a7e8 Author: Alfredo Alvarez Fernandez <[email protected]> AuthorDate: Fri, 19 Feb 2016 07:48:52 +0100 Committer: Ingo Molnar <[email protected]> CommitDate: Mon, 29 Feb 2016 10:29:33 +0100
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 <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Paul E. McKenney <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Sasha Levin <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/1455864533-7536-3-git-send-email-alfredoalvarezernan...@gmail.com Signed-off-by: Ingo Molnar <[email protected]> --- tools/lib/lockdep/tests/AA.c | 8 +++--- tools/lib/lockdep/tests/{AA.c => ABA.c} | 0 tools/lib/lockdep/tests/ABBA_2threads.c | 46 +++++++++++++++++++++++++++++++++ 3 files changed, 50 insertions(+), 4 deletions(-) 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/AA.c b/tools/lib/lockdep/tests/ABA.c similarity index 100% copy from tools/lib/lockdep/tests/AA.c copy to tools/lib/lockdep/tests/ABA.c diff --git a/tools/lib/lockdep/tests/ABBA_2threads.c b/tools/lib/lockdep/tests/ABBA_2threads.c new file mode 100644 index 0000000..cd807d7 --- /dev/null +++ b/tools/lib/lockdep/tests/ABBA_2threads.c @@ -0,0 +1,46 @@ +#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; +}
