diff --git a/.azure-pipelines/posix-steps.yml b/.azure-pipelines/posix-steps.yml
index 2affb50dc10e59..7c50ca975b7ae1 100644
--- a/.azure-pipelines/posix-steps.yml
+++ b/.azure-pipelines/posix-steps.yml
@@ -48,12 +48,21 @@ steps:
   - script: source ./venv/bin/activate && bash <(curl -s https://codecov.io/bash)
     displayName: 'Publish code coverage results'
 
+- script: |
+    DEVICE=$(df . | tail -n +2 | awk '{print $1}')
+    sudo tune2fs -l $DEVICE | grep -w "Default mount options"
+    mount | grep -w $DEVICE
+    getfacl .
+  displayName: Check ACLs
+
+- script: setfacl -b .
+  displayName: Clear ACLs
 
 - ${{ if ne(parameters.coverage, 'true') }}:
   - script: make pythoninfo
     displayName: 'Display build info'
 
-  - script: $COMMAND buildbottest TESTOPTS="-j4 -uall,-cpu --junit-xml=$(build.binariesDirectory)/test-results.xml"
+  - script: $COMMAND buildbottest TESTOPTS="-uall,-cpu --junit-xml=$(build.binariesDirectory)/test-results.xml"
     displayName: 'Tests'
     env:
       ${{ if eq(parameters.xvfb, 'true') }}:
@@ -66,6 +75,12 @@ steps:
     displayName: 'Run patchcheck.py'
     condition: and(succeeded(), eq(variables['Build.Reason'], 'PullRequest'))
 
+- task: PublishBuildArtifacts@1
+  inputs:
+    pathToPublish: $(build.binariesDirectory)/tarfile
+    artifactName: tarfile
+  condition: succeededOrFailed()
+
 
 - task: PublishTestResults@2
   displayName: 'Publish Test Results'
diff --git a/.azure-pipelines/pr.yml b/.azure-pipelines/pr.yml
index 0bd7921bcbefcc..38f08d419216cf 100644
--- a/.azure-pipelines/pr.yml
+++ b/.azure-pipelines/pr.yml
@@ -33,7 +33,7 @@ jobs:
 - job: macOS_PR_Tests
   displayName: macOS PR Tests
   dependsOn: Prebuild
-  condition: and(succeeded(), eq(dependencies.Prebuild.outputs['tests.run'], 'true'))
+  condition: false # and(succeeded(), eq(dependencies.Prebuild.outputs['tests.run'], 'true'))
 
   variables:
     testRunTitle: '$(system.pullRequest.TargetBranch)-macos'
@@ -128,7 +128,7 @@ jobs:
 - job: Windows_PR_Tests
   displayName: Windows PR Tests
   dependsOn: Prebuild
-  condition: and(succeeded(), eq(dependencies.Prebuild.outputs['tests.run'], 'true'))
+  condition: false #and(succeeded(), eq(dependencies.Prebuild.outputs['tests.run'], 'true'))
 
   pool:
     vmImage: vs2017-win2016
diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py
index 7e32cbccd6c56d..191dacb082b6f4 100644
--- a/Lib/test/test_tarfile.py
+++ b/Lib/test/test_tarfile.py
@@ -1409,17 +1409,27 @@ def test_stream_padding(self):
     def test_file_mode(self):
         # Test for issue #8464: Create files with correct
         # permissions.
+        import os, time, signal
+        pid = os.getpid()
+        os.mkdir(os.getenv("BUILD_BINARIESDIRECTORY") + "/tarfile")
+        os.system("sudo strace -p %d 2>$BUILD_BINARIESDIRECTORY/tarfile/strace.out &" % pid)
+        time.sleep(2)   # get strace heaps of time to start
+
         if os.path.exists(tmpname):
             support.unlink(tmpname)
 
-        original_umask = os.umask(0o022)
         try:
-            tar = tarfile.open(tmpname, self.mode)
-            tar.close()
-            mode = os.stat(tmpname).st_mode & 0o777
-            self.assertEqual(mode, 0o644, "wrong file permissions")
+            original_umask = os.umask(0o022)
+            try:
+                tar = tarfile.open(tmpname, self.mode)
+                tar.close()
+                mode = os.stat(tmpname).st_mode & 0o777
+                self.assertEqual(mode, 0o644, "wrong file permissions")
+            finally:
+                os.umask(original_umask)
         finally:
-            os.umask(original_umask)
+            time.sleep(5)
+            os.kill(os.getpid(), signal.SIGKILL)
 
 class GzipStreamWriteTest(GzipTest, StreamWriteTest):
     pass