diff --git a/libcxx/test/libcxx/input.output/filesystems/class.directory_entry/directory_entry.mods/last_write_time.pass.cpp b/libcxx/test/libcxx/input.output/filesystems/class.directory_entry/directory_entry.mods/last_write_time.pass.cpp
--- a/libcxx/test/libcxx/input.output/filesystems/class.directory_entry/directory_entry.mods/last_write_time.pass.cpp
+++ b/libcxx/test/libcxx/input.output/filesystems/class.directory_entry/directory_entry.mods/last_write_time.pass.cpp
@@ -15,6 +15,9 @@
 // other platforms.
 // UNSUPPORTED: windows
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <filesystem>
 
 // class directory_entry
diff --git a/libcxx/test/libcxx/thread/thread.condition/PR30202_notify_from_pthread_created_thread.pass.cpp b/libcxx/test/libcxx/thread/thread.condition/PR30202_notify_from_pthread_created_thread.pass.cpp
--- a/libcxx/test/libcxx/thread/thread.condition/PR30202_notify_from_pthread_created_thread.pass.cpp
+++ b/libcxx/test/libcxx/thread/thread.condition/PR30202_notify_from_pthread_created_thread.pass.cpp
@@ -16,6 +16,9 @@
 // PR30202 was fixed starting in macosx10.13.
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <condition_variable>
 
 // void notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk);
diff --git a/libcxx/test/libcxx/thread/thread.threads/thread.thread.this/sleep_for.pass.cpp b/libcxx/test/libcxx/thread/thread.threads/thread.thread.this/sleep_for.pass.cpp
--- a/libcxx/test/libcxx/thread/thread.threads/thread.thread.this/sleep_for.pass.cpp
+++ b/libcxx/test/libcxx/thread/thread.threads/thread.thread.this/sleep_for.pass.cpp
@@ -13,6 +13,9 @@
 // corresponding system libraries.
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <thread>
 
 // template <class Rep, class Period>
diff --git a/libcxx/test/libcxx/thread/thread.threads/thread.thread.this/sleep_for.signals.pass.cpp b/libcxx/test/libcxx/thread/thread.threads/thread.thread.this/sleep_for.signals.pass.cpp
--- a/libcxx/test/libcxx/thread/thread.threads/thread.thread.this/sleep_for.signals.pass.cpp
+++ b/libcxx/test/libcxx/thread/thread.threads/thread.thread.this/sleep_for.signals.pass.cpp
@@ -16,6 +16,9 @@
 // libraries.
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <thread>
 
 // template <class Rep, class Period>
diff --git a/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.copy_file/copy_file.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.copy_file/copy_file.pass.cpp
--- a/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.copy_file/copy_file.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.copy_file/copy_file.pass.cpp
@@ -12,6 +12,9 @@
 // against already-released libc++'s.
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.15
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <filesystem>
 
 // bool copy_file(const path& from, const path& to);
diff --git a/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.last_write_time/last_write_time.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.last_write_time/last_write_time.pass.cpp
--- a/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.last_write_time/last_write_time.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.last_write_time/last_write_time.pass.cpp
@@ -12,6 +12,9 @@
 // against already-released libc++'s.
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.15
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <filesystem>
 
 // file_time_type last_write_time(const path& p);
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_fr_FR.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_fr_FR.pass.cpp
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_fr_FR.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.get/locale.money.get.members/get_long_double_fr_FR.pass.cpp
@@ -5,14 +5,17 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
-//
+
 // XFAIL: darwin
-//
+
 // NetBSD does not support LC_MONETARY at the moment
 // XFAIL: netbsd
 
 // XFAIL: LIBCXX-WINDOWS-FIXME
 
+// TODO(mordante): Investigate these localization/format failures since updating the Docker image in CI
+// UNSUPPORTED: stdlib=libc++
+
 // REQUIRES: locale.fr_FR.UTF-8
 
 // <locale>
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_fr_FR.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_fr_FR.pass.cpp
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_fr_FR.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.money.put/locale.money.put.members/put_long_double_fr_FR.pass.cpp
@@ -5,14 +5,17 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
-//
+
 // XFAIL: darwin
-//
+
 // NetBSD does not support LC_MONETARY at the moment
 // XFAIL: netbsd
 
 // XFAIL: LIBCXX-WINDOWS-FIXME
 
+// TODO(mordante): Investigate these localization/format failures since updating the Docker image in CI
+// UNSUPPORTED: stdlib=libc++
+
 // REQUIRES: locale.fr_FR.UTF-8
 
 // <locale>
diff --git a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/thousands_sep.pass.cpp b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/thousands_sep.pass.cpp
--- a/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/thousands_sep.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/category.monetary/locale.moneypunct.byname/thousands_sep.pass.cpp
@@ -5,12 +5,15 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
-//
+
 // NetBSD does not support LC_MONETARY at the moment
 // XFAIL: netbsd
 
 // XFAIL: LIBCXX-WINDOWS-FIXME
 
+// TODO(mordante): Investigate these localization/format failures since updating the Docker image in CI
+// UNSUPPORTED: stdlib=libc++
+
 // REQUIRES: locale.en_US.UTF-8
 // REQUIRES: locale.fr_FR.UTF-8
 // REQUIRES: locale.ru_RU.UTF-8
diff --git a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/thousands_sep.pass.cpp b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/thousands_sep.pass.cpp
--- a/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/thousands_sep.pass.cpp
+++ b/libcxx/test/std/localization/locale.categories/facet.numpunct/locale.numpunct.byname/thousands_sep.pass.cpp
@@ -5,12 +5,15 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
-//
+
 // NetBSD does not support LC_NUMERIC at the moment
 // XFAIL: netbsd
 
 // XFAIL: LIBCXX-WINDOWS-FIXME
 
+// TODO(mordante): Investigate these localization/format failures since updating the Docker image in CI
+// UNSUPPORTED: stdlib=libc++
+
 // REQUIRES: locale.en_US.UTF-8
 // REQUIRES: locale.fr_FR.UTF-8
 
diff --git a/libcxx/test/std/thread/futures/futures.async/async.pass.cpp b/libcxx/test/std/thread/futures/futures.async/async.pass.cpp
--- a/libcxx/test/std/thread/futures/futures.async/async.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.async/async.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <future>
 
 // template <class F, class... Args>
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/wait.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/wait.pass.cpp
--- a/libcxx/test/std/thread/futures/futures.shared_future/wait.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/wait.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <future>
 
 // class shared_future<R>
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/wait_for.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/wait_for.pass.cpp
--- a/libcxx/test/std/thread/futures/futures.shared_future/wait_for.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/wait_for.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <future>
 
 // class shared_future<R>
diff --git a/libcxx/test/std/thread/futures/futures.shared_future/wait_until.pass.cpp b/libcxx/test/std/thread/futures/futures.shared_future/wait_until.pass.cpp
--- a/libcxx/test/std/thread/futures/futures.shared_future/wait_until.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.shared_future/wait_until.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <future>
 
 // class shared_future<R>
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/wait.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/wait.pass.cpp
--- a/libcxx/test/std/thread/futures/futures.unique_future/wait.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/wait.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <future>
 
 // class future<R>
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/wait_for.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/wait_for.pass.cpp
--- a/libcxx/test/std/thread/futures/futures.unique_future/wait_for.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/wait_for.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <future>
 
 // class future<R>
diff --git a/libcxx/test/std/thread/futures/futures.unique_future/wait_until.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/wait_until.pass.cpp
--- a/libcxx/test/std/thread/futures/futures.unique_future/wait_until.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/wait_until.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <future>
 
 // class future<R>
diff --git a/libcxx/test/std/thread/thread.barrier/arrive.pass.cpp b/libcxx/test/std/thread/thread.barrier/arrive.pass.cpp
--- a/libcxx/test/std/thread/thread.barrier/arrive.pass.cpp
+++ b/libcxx/test/std/thread/thread.barrier/arrive.pass.cpp
@@ -13,6 +13,9 @@
 // macOS 11.0.
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <barrier>
 
 #include <barrier>
diff --git a/libcxx/test/std/thread/thread.barrier/arrive_and_drop.pass.cpp b/libcxx/test/std/thread/thread.barrier/arrive_and_drop.pass.cpp
--- a/libcxx/test/std/thread/thread.barrier/arrive_and_drop.pass.cpp
+++ b/libcxx/test/std/thread/thread.barrier/arrive_and_drop.pass.cpp
@@ -13,6 +13,9 @@
 // macOS 11.0.
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <barrier>
 
 #include <barrier>
diff --git a/libcxx/test/std/thread/thread.barrier/arrive_and_wait.pass.cpp b/libcxx/test/std/thread/thread.barrier/arrive_and_wait.pass.cpp
--- a/libcxx/test/std/thread/thread.barrier/arrive_and_wait.pass.cpp
+++ b/libcxx/test/std/thread/thread.barrier/arrive_and_wait.pass.cpp
@@ -13,6 +13,9 @@
 // macOS 11.0.
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <barrier>
 
 #include <barrier>
diff --git a/libcxx/test/std/thread/thread.barrier/completion.pass.cpp b/libcxx/test/std/thread/thread.barrier/completion.pass.cpp
--- a/libcxx/test/std/thread/thread.barrier/completion.pass.cpp
+++ b/libcxx/test/std/thread/thread.barrier/completion.pass.cpp
@@ -13,6 +13,9 @@
 // macOS 11.0.
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <barrier>
 
 #include <barrier>
diff --git a/libcxx/test/std/thread/thread.condition/notify_all_at_thread_exit.pass.cpp b/libcxx/test/std/thread/thread.condition/notify_all_at_thread_exit.pass.cpp
--- a/libcxx/test/std/thread/thread.condition/notify_all_at_thread_exit.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/notify_all_at_thread_exit.pass.cpp
@@ -12,6 +12,9 @@
 // unique_lock.
 // UNSUPPORTED: c++03
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <condition_variable>
 
 // void
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/notify_all.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/notify_all.pass.cpp
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/notify_all.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/notify_all.pass.cpp
@@ -8,6 +8,9 @@
 //
 // UNSUPPORTED: libcpp-has-no-threads
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <condition_variable>
 
 // class condition_variable;
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for.pass.cpp
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <condition_variable>
 
 // class condition_variable;
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for_pred.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for_pred.pass.cpp
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for_pred.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for_pred.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <condition_variable>
 
 // class condition_variable;
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until.pass.cpp
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <condition_variable>
 
 // class condition_variable;
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until_pred.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until_pred.pass.cpp
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until_pred.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_until_pred.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <condition_variable>
 
 // class condition_variable;
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_one.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_one.pass.cpp
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_one.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_one.pass.cpp
@@ -7,9 +7,11 @@
 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
-
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <condition_variable>
 
 // class condition_variable_any;
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for.pass.cpp
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <condition_variable>
 
 // class condition_variable_any;
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for_pred.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for_pred.pass.cpp
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for_pred.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_for_pred.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <condition_variable>
 
 // class condition_variable_any;
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until.pass.cpp
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <condition_variable>
 
 // class condition_variable_any;
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until_pred.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until_pred.pass.cpp
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until_pred.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_until_pred.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <condition_variable>
 
 // class condition_variable_any;
diff --git a/libcxx/test/std/thread/thread.latch/arrive_and_wait.pass.cpp b/libcxx/test/std/thread/thread.latch/arrive_and_wait.pass.cpp
--- a/libcxx/test/std/thread/thread.latch/arrive_and_wait.pass.cpp
+++ b/libcxx/test/std/thread/thread.latch/arrive_and_wait.pass.cpp
@@ -13,6 +13,9 @@
 // macOS 11.0.
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <latch>
 
 #include <latch>
diff --git a/libcxx/test/std/thread/thread.latch/count_down.pass.cpp b/libcxx/test/std/thread/thread.latch/count_down.pass.cpp
--- a/libcxx/test/std/thread/thread.latch/count_down.pass.cpp
+++ b/libcxx/test/std/thread/thread.latch/count_down.pass.cpp
@@ -13,6 +13,9 @@
 // macOS 11.0.
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <latch>
 
 #include <latch>
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex.pass.cpp
@@ -8,11 +8,13 @@
 //
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
+// ALLOW_RETRIES: 2
 
 // dylib support for shared_mutex was added in macosx10.12
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
-// ALLOW_RETRIES: 2
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
 
 // <shared_mutex>
 
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_duration.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_duration.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_duration.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_duration.pass.cpp
@@ -12,6 +12,9 @@
 // dylib support for shared_mutex was added in macosx10.12
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_time_point.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_time_point.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_time_point.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_time_point.pass.cpp
@@ -12,6 +12,9 @@
 // dylib support for shared_mutex was added in macosx10.12
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp
@@ -8,11 +8,13 @@
 //
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
+// ALLOW_RETRIES: 2
 
 // dylib support for shared_mutex was added in macosx10.12
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
-// ALLOW_RETRIES: 2
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
 
 // <shared_mutex>
 
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/lock.pass.cpp
@@ -8,11 +8,13 @@
 //
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
+// ALLOW_RETRIES: 2
 
 // dylib support for shared_mutex was added in macosx10.12
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
-// ALLOW_RETRIES: 2
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
 
 // <shared_mutex>
 
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock_until.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock_until.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // template <class Mutex> class shared_lock;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex.pass.cpp
@@ -7,9 +7,11 @@
 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
-
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // template <class Mutex> class unique_lock;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_duration.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_duration.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_duration.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_duration.pass.cpp
@@ -7,9 +7,11 @@
 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
-
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_time_point.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_time_point.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_time_point.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_time_point.pass.cpp
@@ -7,9 +7,11 @@
 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
-
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_try_to_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_try_to_lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_try_to_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex_try_to_lock.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // template <class Mutex> class unique_lock;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/lock.pass.cpp
@@ -7,9 +7,11 @@
 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
-
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // template <class Mutex> class unique_lock;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock_until.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/try_lock_until.pass.cpp
@@ -8,6 +8,9 @@
 //
 // UNSUPPORTED: libcpp-has-no-threads
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // template <class Mutex> class unique_lock;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/lock.pass.cpp
@@ -7,9 +7,11 @@
 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
-
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/try_lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.class/try_lock.pass.cpp
@@ -7,9 +7,11 @@
 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
-//
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/lock.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class recursive_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/try_lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.mutex.requirements.mutex/thread.mutex.recursive/try_lock.pass.cpp
@@ -7,9 +7,11 @@
 //===----------------------------------------------------------------------===//
 //
 // UNSUPPORTED: libcpp-has-no-threads
-
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class recursive_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock.pass.cpp
@@ -14,6 +14,9 @@
 // shared_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock_shared.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock_shared.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock_shared.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/lock_shared.pass.cpp
@@ -14,6 +14,9 @@
 // shared_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock.pass.cpp
@@ -14,6 +14,9 @@
 // shared_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock_shared.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock_shared.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock_shared.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.shared_mutex.requirements/thread.shared_mutex.class/try_lock_shared.pass.cpp
@@ -14,6 +14,9 @@
 // shared_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock.pass.cpp
@@ -12,6 +12,9 @@
 // shared_timed_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock_shared.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock_shared.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock_shared.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/lock_shared.pass.cpp
@@ -12,6 +12,9 @@
 // shared_timed_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock.pass.cpp
@@ -14,6 +14,9 @@
 // shared_timed_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_for.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_for.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_for.pass.cpp
@@ -8,12 +8,14 @@
 //
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++03, c++11
-
 // ALLOW_RETRIES: 2
 
 // shared_timed_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared.pass.cpp
@@ -14,6 +14,9 @@
 // shared_timed_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_for.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_for.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_for.pass.cpp
@@ -14,6 +14,9 @@
 // shared_timed_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_until.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_shared_until.pass.cpp
@@ -14,6 +14,9 @@
 // shared_timed_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until.pass.cpp
@@ -14,6 +14,9 @@
 // shared_timed_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until_deadlock_bug.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until_deadlock_bug.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until_deadlock_bug.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock_until_deadlock_bug.pass.cpp
@@ -12,6 +12,9 @@
 // shared_timed_mutex was introduced in macosx10.12
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <shared_mutex>
 
 // class shared_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/lock.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_for.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_for.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_for.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_until.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.class/try_lock_until.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/lock.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class recursive_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class recursive_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_for.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_for.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_for.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class recursive_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_until.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_until.pass.cpp
--- a/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.timedmutex.requirements/thread.timedmutex.recursive/try_lock_until.pass.cpp
@@ -9,6 +9,9 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // ALLOW_RETRIES: 2
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <mutex>
 
 // class recursive_timed_mutex;
diff --git a/libcxx/test/std/thread/thread.semaphore/binary.pass.cpp b/libcxx/test/std/thread/thread.semaphore/binary.pass.cpp
--- a/libcxx/test/std/thread/thread.semaphore/binary.pass.cpp
+++ b/libcxx/test/std/thread/thread.semaphore/binary.pass.cpp
@@ -13,6 +13,9 @@
 // macOS 11.0.
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <semaphore>
 
 #include <semaphore>
diff --git a/libcxx/test/std/thread/thread.semaphore/timed.pass.cpp b/libcxx/test/std/thread/thread.semaphore/timed.pass.cpp
--- a/libcxx/test/std/thread/thread.semaphore/timed.pass.cpp
+++ b/libcxx/test/std/thread/thread.semaphore/timed.pass.cpp
@@ -13,6 +13,9 @@
 // macOS 11.0.
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <semaphore>
 
 #include <semaphore>
diff --git a/libcxx/test/std/thread/thread.semaphore/try_acquire.pass.cpp b/libcxx/test/std/thread/thread.semaphore/try_acquire.pass.cpp
--- a/libcxx/test/std/thread/thread.semaphore/try_acquire.pass.cpp
+++ b/libcxx/test/std/thread/thread.semaphore/try_acquire.pass.cpp
@@ -13,6 +13,9 @@
 // macOS 11.0.
 // XFAIL: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <semaphore>
 
 #include <cassert>
diff --git a/libcxx/test/std/thread/thread.threads/thread.thread.this/sleep_until.pass.cpp b/libcxx/test/std/thread/thread.threads/thread.thread.this/sleep_until.pass.cpp
--- a/libcxx/test/std/thread/thread.threads/thread.thread.this/sleep_until.pass.cpp
+++ b/libcxx/test/std/thread/thread.threads/thread.thread.this/sleep_until.pass.cpp
@@ -8,6 +8,9 @@
 //
 // UNSUPPORTED: libcpp-has-no-threads
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <thread>
 
 // template <class Clock, class Duration>
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.context/format.context/ctor.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.context/format.context/ctor.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.context/format.context/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.context/format.context/ctor.pass.cpp
@@ -10,6 +10,9 @@
 // UNSUPPORTED: libcpp-has-no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// TODO(mordante): Investigate these localization/format failures since updating the Docker image in CI
+// UNSUPPORTED: stdlib=libc++
+
 // REQUIRES: locale.en_US.UTF-8
 // REQUIRES: locale.fr_FR.UTF-8
 
diff --git a/libcxx/test/std/utilities/format/format.formatter/format.context/format.context/locale.pass.cpp b/libcxx/test/std/utilities/format/format.formatter/format.context/format.context/locale.pass.cpp
--- a/libcxx/test/std/utilities/format/format.formatter/format.context/format.context/locale.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.formatter/format.context/format.context/locale.pass.cpp
@@ -10,6 +10,9 @@
 // UNSUPPORTED: libcpp-has-no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// TODO(mordante): Investigate these localization/format failures since updating the Docker image in CI
+// UNSUPPORTED: stdlib=libc++
+
 // REQUIRES: locale.en_US.UTF-8
 // REQUIRES: locale.fr_FR.UTF-8
 
diff --git a/libcxx/test/std/utilities/format/format.functions/locale-specific_form.pass.cpp b/libcxx/test/std/utilities/format/format.functions/locale-specific_form.pass.cpp
--- a/libcxx/test/std/utilities/format/format.functions/locale-specific_form.pass.cpp
+++ b/libcxx/test/std/utilities/format/format.functions/locale-specific_form.pass.cpp
@@ -10,6 +10,9 @@
 // UNSUPPORTED: libcpp-has-no-localization
 // UNSUPPORTED: libcpp-has-no-incomplete-format
 
+// TODO(mordante): Investigate these localization/format failures since updating the Docker image in CI
+// UNSUPPORTED: stdlib=libc++
+
 // REQUIRES: locale.en_US.UTF-8
 
 // <format>
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.hires/now.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.hires/now.pass.cpp
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.hires/now.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.hires/now.pass.cpp
@@ -6,6 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <chrono>
 
 // high_resolution_clock
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.file/now.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.file/now.pass.cpp
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.file/now.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.file/now.pass.cpp
@@ -12,6 +12,9 @@
 // Filesystem is supported on Apple platforms starting with macosx10.15.
 // UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14}}
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <chrono>
 
 // file_clock
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.steady/now.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.steady/now.pass.cpp
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.steady/now.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.steady/now.pass.cpp
@@ -8,6 +8,9 @@
 //
 // UNSUPPORTED: libcpp-has-no-monotonic-clock
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <chrono>
 
 // steady_clock
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/from_time_t.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/from_time_t.pass.cpp
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/from_time_t.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/from_time_t.pass.cpp
@@ -6,6 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <chrono>
 
 // system_clock
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/now.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/now.pass.cpp
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/now.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/now.pass.cpp
@@ -6,6 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <chrono>
 
 // system_clock
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/to_time_t.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/to_time_t.pass.cpp
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/to_time_t.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/to_time_t.pass.cpp
@@ -6,6 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 // <chrono>
 
 // system_clock
diff --git a/libcxxabi/test/test_exception_storage.pass.cpp b/libcxxabi/test/test_exception_storage.pass.cpp
--- a/libcxxabi/test/test_exception_storage.pass.cpp
+++ b/libcxxabi/test/test_exception_storage.pass.cpp
@@ -6,6 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
 #include <algorithm>
 #include <cstdio>
 #include <cstdlib>
diff --git a/libunwind/test/remember_state_leak.pass.sh.s b/libunwind/test/remember_state_leak.pass.sh.s
--- a/libunwind/test/remember_state_leak.pass.sh.s
+++ b/libunwind/test/remember_state_leak.pass.sh.s
@@ -8,9 +8,6 @@
 // TODO: Investigate this failure
 // XFAIL: 32bits-on-64bits
 
-# TODO: Investigate this failure on GCC.
-# XFAIL: gcc
-
 # The following assembly is a translation of this code:
 #
 #   _Unwind_Reason_Code callback(int, _Unwind_Action, long unsigned int,