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| author | Edward Liaw <edliaw@google.com> | 2024-10-03 21:17:10 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-10-17 00:28:06 -0700 |
| commit | e61ef21e27e8deed8c474e9f47f4aa7bc37e138c (patch) | |
| tree | 85e2c6ba8f5b7dbc53d63cd1cb385c1cdeef0521 /tools/testing/selftests/mm/uffd-unit-tests.c | |
| parent | 963a7f4d3b90ee195b895ca06b95757fcba02d1a (diff) | |
| download | linux-e61ef21e27e8deed8c474e9f47f4aa7bc37e138c.tar.gz linux-e61ef21e27e8deed8c474e9f47f4aa7bc37e138c.tar.bz2 linux-e61ef21e27e8deed8c474e9f47f4aa7bc37e138c.zip | |
selftests/mm: replace atomic_bool with pthread_barrier_t
Patch series "selftests/mm: fix deadlock after pthread_create".
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.
Update the synchronization primitive to use pthread_barrier instead of
atomic_bool.
Apply the same fix to the wp-fork-with-event test.
This patch (of 2):
Swap synchronization primitive with pthread_barrier, so that stdatomic.h
does not need to be included.
The synchronization is needed on Android ARM64; we see a deadlock with
pthread_create when the parent thread races forward before the child has a
chance to start doing work.
Link: https://lkml.kernel.org/r/20241003211716.371786-1-edliaw@google.com
Link: https://lkml.kernel.org/r/20241003211716.371786-2-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>
Diffstat (limited to 'tools/testing/selftests/mm/uffd-unit-tests.c')
| -rw-r--r-- | tools/testing/selftests/mm/uffd-unit-tests.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c index b3d21eed203d..3db2296ac631 100644 --- a/tools/testing/selftests/mm/uffd-unit-tests.c +++ b/tools/testing/selftests/mm/uffd-unit-tests.c @@ -774,7 +774,7 @@ static void uffd_sigbus_test_common(bool wp) char c; struct uffd_args args = { 0 }; - ready_for_fork = false; + pthread_barrier_init(&ready_for_fork, NULL, 2); fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK); @@ -791,8 +791,9 @@ static void uffd_sigbus_test_common(bool wp) if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args)) err("uffd_poll_thread create"); - while (!ready_for_fork) - ; /* Wait for the poll_thread to start executing before forking */ + /* Wait for child thread to start before forking */ + pthread_barrier_wait(&ready_for_fork); + pthread_barrier_destroy(&ready_for_fork); pid = fork(); if (pid < 0) @@ -833,7 +834,7 @@ static void uffd_events_test_common(bool wp) char c; struct uffd_args args = { 0 }; - ready_for_fork = false; + pthread_barrier_init(&ready_for_fork, NULL, 2); fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK); if (uffd_register(uffd, area_dst, nr_pages * page_size, @@ -844,8 +845,9 @@ static void uffd_events_test_common(bool wp) if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args)) err("uffd_poll_thread create"); - while (!ready_for_fork) - ; /* Wait for the poll_thread to start executing before forking */ + /* Wait for child thread to start before forking */ + pthread_barrier_wait(&ready_for_fork); + pthread_barrier_destroy(&ready_for_fork); pid = fork(); if (pid < 0) |