The quilt patch titled Subject: Revert "selftests/mm: fix deadlock for fork after pthread_create on ARM" has been removed from the -mm tree. Its filename was revert-selftests-mm-fix-deadlock-for-fork-after-pthread_create-on-arm.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------ From: Edward Liaw edliaw@google.com Subject: Revert "selftests/mm: fix deadlock for fork after pthread_create on ARM" Date: Fri, 18 Oct 2024 17:17:22 +0000
Patch series "selftests/mm: revert pthread_barrier change"
On Android arm, pthread_create followed by a fork caused a deadlock in the case where the fork required work to be completed by the created thread.
The previous patches incorrectly assumed that the parent would always initialize the pthread_barrier for the child thread. This reverts the change and replaces the fix for wp-fork-with-event with the original use of atomic_bool.
This patch (of 3):
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.
Link: https://lkml.kernel.org/r/20241018171734.2315053-1-edliaw@google.com Link: https://lkml.kernel.org/r/20241018171734.2315053-2-edliaw@google.com Fixes: e142cc87ac4e ("fix deadlock for fork after pthread_create on ARM") Signed-off-by: Edward Liaw edliaw@google.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Peter Xu peterx@redhat.com Cc: Shuah Khan shuah@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
tools/testing/selftests/mm/uffd-unit-tests.c | 7 ------- 1 file changed, 7 deletions(-)
--- a/tools/testing/selftests/mm/uffd-unit-tests.c~revert-selftests-mm-fix-deadlock-for-fork-after-pthread_create-on-arm +++ a/tools/testing/selftests/mm/uffd-unit-tests.c @@ -241,9 +241,6 @@ static void *fork_event_consumer(void *d 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, b
/* 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(); _
Patches currently in -mm which might be from edliaw@google.com are