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Issue metadata

Status: Fixed
Closed: May 2017
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 0
Type: Bug

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Leftover registry entries on bots cause subsequent tests to fail

Project Member Reported by, May 12 2017

Issue description

"CloudPolicyManagerTest.RegisterFails" is flaky.

This issue was created automatically by the chromium-try-flakes app. Please find the right owner to fix the respective test/step and assign this issue to them. If the step/test is infrastructure-related, please add Infra-Troopers label and change issue status to Untriaged. When done, please remove the issue from Sheriff Bug Queue by removing the Sheriff-Chromium label.

We have detected 3 recent flakes. List of all flakes can be found at

Flaky tests should be disabled within 30 minutes unless culprit CL is found and reverted. Please see more details here:
Labels: -Sheriff-Chromium
Status: Assigned (was: Untriaged)
This is due to a misconfigured bot that has policies configured on the machine for some reason. I'm reaching out to troopers to fix it.
Error is:

[ RUN      ] CloudPolicyManagerTest.RegisterFails
[4660:5036:0512/] Unknown policy: StringPolicy
[4660:5036:0512/] Unknown policy: StringPolicy
[4356:4724:0512/] Windows versions earlier than 8 are not supported.
[4660:5036:0512/] There are pre-existing policies in this machine: {
   "StringPolicy": "hklm"
e:\b\c\b\win\src\chrome\browser\policy\cloud\ error: Value of: PolicyServiceIsEmpty(g_browser_process->policy_service())
  Actual: false
Expected: true
Pre-existing policies in this machine will make this test fail.
	policy::CloudPolicyManagerTest_RegisterFails_Test::RunTestOnMainThread [0x006B3799+41]
	content::BrowserTestBase::ProxyRunTestOnMainThreadLoop [0x01C34E69+233]
	ChromeBrowserMainParts::PreMainMessageLoopRunImpl [0x02381B67+3320]
	ChromeBrowserMainParts::PreMainMessageLoopRun [0x02380E37+167]
	content::BrowserMainLoop::PreMainMessageLoopRun [0x00DEB8D0+112]
	content::StartupTaskRunner::RunAllTasksNow [0x0104EFC9+35]
	content::BrowserMainLoop::CreateStartupTasks [0x00DE986E+394]
	content::BrowserMainRunnerImpl::Initialize [0x00DECAB0+704]
	content::BrowserMain [0x00DE83A5+117]
	content::RunNamedProcessTypeMain [0x01AAD43C+206]
	content::ContentMainRunnerImpl::Run [0x01AAD33D+413]
	service_manager::Main [0x02A12696+524]
	content::ContentMain [0x01AAC9E8+39]
	content::BrowserTestBase::SetUp [0x01C35392+866]
	InProcessBrowserTest::SetUp [0x01B7EF36+310]
	testing::internal::HandleExceptionsInMethodIfSupported<testing::TestCase,void> [0x00A43FAD+32]
	testing::Test::Run [0x00A4B09F+51]
	testing::TestInfo::Run [0x00A4B24A+126]
	testing::TestCase::Run [0x00A4B175+133]
	testing::internal::UnitTestImpl::RunAllTests [0x00A4B501+433]
	testing::internal::HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl,bool> [0x00A43FF1+32]
	testing::UnitTest::Run [0x00A4B31E+133]
	base::TestSuite::Run [0x01B8E786+95]
	ChromeTestSuiteRunner::RunTestSuite [0x040958F8+40]
	content::LaunchTests [0x01C2DFC0+583]
	LaunchChromeTests [0x040958B4+62]
	main [0x040956C9+63]
	__scrt_common_main_seh [0x0404534B+249] (f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:253)
	BaseThreadInitThunk [0x7705337A+18]
	RtlInitializeExceptionChain [0x775892B2+99]
	RtlInitializeExceptionChain [0x77589285+54]

Comment 5 by, May 12 2017

 Issue 721694  has been merged into this issue.

Comment 6 by, May 15 2017

Components: Infra>Labs
This is a request to check os:Windows-7-SP1, gpu:none Swarming bots for consistency.

Comment 7 by, May 16 2017

It looks like the offending registry key is  HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Chromium /v StringPolicy

It was found and deleted on 4 swarming slaves: vm33-m4 vm84-m4 vm359-m4 vm438-m4

Comment 8 by, May 19 2017

Labels: -Pri-1 Pri-0
This is causing major flakes on the CQ and makes the diagnosis of another P0 (issue 721245) harder.

Latest occurence:
Summary: Leftover registry entries on bots cause subsequent tests to fail (was: "CloudPolicyManagerTest.RegisterFails" is flaky)
Reassigning to pschmidt to clean up this bot too.

Anyone have any idea where these reg entries are coming from? I have to presume it's some test not getting cleaned up (maybe after a failure) - what's the mechanism by which we clean up leftover registry entries after tests?
Julian, looks like it's the class leaving this behind:

What's supposed to clean up after this test?
Hmm good question. I will disable this test for now and refernce this bug until we find a better way to do that. I think the installer tests have some good way to virtualize the registry operations.
Hrm, seems to use RegOverridePredefKey to re-map the HKLM / HKCU registry keys to temporary registry hives created for that unittast. MSDN says that this is a per-process override.

I've seen these flaky tests in browser_tests, but the override only happens in unit_tests - how could this be? Would it mean that the original re-direction fails so the test actually makes real changes to registry which persist on the machine?

BTW, it seems a bit similar to  bug 688878 .
+grt who had a CL to improve the registry key override logic there.
After offline discussion with pastarmovj@, we think we found the reason, same as in  bug 688878 :
The tests just wrap the registry key overriding mechanism in ASSERT_* macros, but this happens in subroutines, so if it fails, we continue writing to the realy registry keys.

Secondly, there is the possibility that if deleting the "temp" keys fails, these will be re-used by another tests, because the temp keys are keyed by process ID.

So, we will change two things:
(1) ensure that nothing is written (tests fail hard) if registry key override fails (ASSERT_NO_FATAL_FAILURE like in grt@'s CL referenced above)
(2) if temp registry keys exist from a previous test, first delete them before re-creating them.
Status: Started (was: Assigned)
Project Member

Comment 15 by, May 19 2017

The following revision refers to this bug:

commit 1059e59ba99809a03a245e7f55a98efba63567d6
Author: pmarko <>
Date: Fri May 19 13:23:01 2017

Fail tests fast if Windows registry key override fails

policy_loader_win_unittest uses RegOverridePredefKey to remap registry
keys to a temporary key for the duration of the test. If this remapping
fails, the test should fail fast to avoid accidentally creating
persistent changes in the machine's registry.
This is done by moving the remap step into the test's SetUp() method.
gtest documentation says that the test will not continue if an ASSERT
fails in SetUp()[1][2].
Also, we now delete the temporary registry keys if they already exist.
These are keyed by the process id, so a subsequent test could reuse an
existing temporary key if the previous test (with the same process id)
crashed and failed to clean up.


BUG= 721691 

Cr-Commit-Position: refs/heads/master@{#473174}


Status: Fixed (was: Started)
 Issue 722246  has been merged into this issue.

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