The quilt patch titled Subject: selftests/mm: fix deadlock for fork after pthread_create on ARM has been removed from the -mm tree. Its filename was 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: selftests/mm: fix deadlock for fork after pthread_create on ARM Date: Thu, 3 Oct 2024 21:17:11 +0000

On Android with arm, there is some synchronization needed to avoid a deadlock when forking after pthread_create.

Link: https://lkml.kernel.org/r/20241003211716.371786-3-edliaw@google.com Fixes: cff294582798 ("selftests/mm: extend and rename uffd pagemap test") Signed-off-by: Edward Liaw edliaw@google.com Cc: Lokesh Gidra lokeshgidra@google.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 insertions(+)

--- a/tools/testing/selftests/mm/uffd-unit-tests.c~selftests-mm-fix-deadlock-for-fork-after-pthread_create-on-arm +++ a/tools/testing/selftests/mm/uffd-unit-tests.c @@ -241,6 +241,9 @@ 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));

@@ -308,8 +311,12 @@ 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