[PATCH 1/3] Revert "selftests/mm: fix deadlock for fork after pthread_create on ARM"

[Edward Liaw]

This reverts commit e142cc87ac4ec618f2ccf5f68aedcd6e28a59d9d.

fork_event_consumer may be called by other tests that do not initialize
the pthread_barrier, so this approach is not correct.  The subsequent
patch will revert to using atomic_bool instead.

Fixes: e142cc87ac4e ("fix deadlock for fork after pthread_create on ARM")
CC: Ryan Roberts <ryan.robe...@arm.com>
Signed-off-by: Edward Liaw <edl...@google.com>
---
 tools/testing/selftests/mm/uffd-unit-tests.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c 
b/tools/testing/selftests/mm/uffd-unit-tests.c
index c8a3b1c7edff..3db2296ac631 100644
--- a/tools/testing/selftests/mm/uffd-unit-tests.c
+++ b/tools/testing/selftests/mm/uffd-unit-tests.c
@@ -241,9 +241,6 @@ static void *fork_event_consumer(void *data)
        fork_event_args *args = data;
        struct uffd_msg msg = { 0 };
 
-       /* Ready for parent thread to fork */
-       pthread_barrier_wait(&ready_for_fork);
-
        /* Read until a full msg received */
        while (uffd_read_msg(args->parent_uffd, &msg));
 
@@ -311,12 +308,8 @@ static int pagemap_test_fork(int uffd, bool with_event, 
bool test_pin)
 
        /* Prepare a thread to resolve EVENT_FORK */
        if (with_event) {
-               pthread_barrier_init(&ready_for_fork, NULL, 2);
                if (pthread_create(&thread, NULL, fork_event_consumer, &args))
                        err("pthread_create()");
-               /* Wait for child thread to start before forking */
-               pthread_barrier_wait(&ready_for_fork);
-               pthread_barrier_destroy(&ready_for_fork);
        }
 
        child = fork();
-- 
2.47.0.105.g07ac214952-goog