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8235211: serviceability/attach/RemovingUnixDomainSocketTest.java fails with AttachNotSupportedException: Unable to open socket file #32

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@navyxliu navyxliu commented Apr 5, 2022

Hi,

Could you review this backport of 8235211? This is a follow up of JDK-8225690.

This patch can't be applied to jdk8u cleanly. We replace os::naked_yield with os::yield(), which is available in jdk8u and have same implementations on Linux/BSD/AIX. Except for that, all other changes are just path adjustment.

There's a deadlock in the original backport. Both Signal dispatcher(refer to S for short) and AttachListener(A) are Java Threads. Therefore, they are subject to safepoint synchronization.

A sets _state to AL_INITIALIZED and then get blocked at a safepoint(maybe AttachListener::dequeue).
If the socket file is deleted and JVM receive SIGQUIT the, S realizes that the socket file has gone in check_socket_file and start to reinitialize it. It falls into this loop and prevent itself from reaching the safepoint.

     while (AttachListener::transit_state(AL_INITIALIZING,
                                           AL_NOT_INITIALIZED) != AL_NOT_INITIALIZED) {
        os::naked_yield();
      }

If A waked up and realized that the socket has gone, it would set _state to AL_NOT_INITIALIZED. Current code is adeadlock. A can’t wake up because S hasn’t reached the safepoint yet. S can’t reach the safepoint because A hasn’t set _state to AL_NOT_INITIALIZED. This patch avoids the deadlock by trapping into blocked state before the loop.


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  • Change must not contain extraneous whitespace
  • Commit message must refer to an issue
  • Change must be properly reviewed (1 review required, with at least 1 reviewer)

Issues

  • JDK-8235211: serviceability/attach/RemovingUnixDomainSocketTest.java fails with AttachNotSupportedException: Unable to open socket file
  • JDK-8244973: serviceability/attach/RemovingUnixDomainSocketTest.java fails "stderr was not empty"

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Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk8u-dev pull/32/head:pull/32
$ git checkout pull/32

Update a local copy of the PR:
$ git checkout pull/32
$ git pull https://git.openjdk.java.net/jdk8u-dev pull/32/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 32

View PR using the GUI difftool:
$ git pr show -t 32

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk8u-dev/pull/32.diff

Xin Liu added 2 commits Apr 5, 2022
…s with AttachNotSupportedException: Unable to open socket file
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👋 Welcome back xliu! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

@openjdk openjdk bot added the rfr label Apr 5, 2022
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@mlbridge mlbridge bot commented Apr 5, 2022

Webrevs

@navyxliu navyxliu changed the title 8235211: serviceability/attach/RemovingUnixDomainSocketTest.java fails with AttachNotSupportedException: Unable to open socket file Backport 073e095e6053550b17b1daf33df2be4f4c4b40ad Apr 5, 2022
@openjdk openjdk bot changed the title Backport 073e095e6053550b17b1daf33df2be4f4c4b40ad 8235211: serviceability/attach/RemovingUnixDomainSocketTest.java fails with AttachNotSupportedException: Unable to open socket file Apr 5, 2022
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This backport pull request has now been updated with issue from the original commit.

@openjdk openjdk bot added the backport label Apr 5, 2022
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@navyxliu navyxliu commented Apr 5, 2022

/issue add JDK-8244973

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@openjdk openjdk bot commented Apr 5, 2022

@navyxliu
Adding additional issue to issue list: 8244973: serviceability/attach/RemovingUnixDomainSocketTest.java fails "stderr was not empty".

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@phohensee phohensee left a comment

I compared with openjdk/jdk11u-dev#153.

Lgtm, except there's a missing import in RemovingUnixDomainSocketTest.java and LingeredApp.java, vis

import jdk.test.lib.Utils;

Currently, RemovingUnixDomainSocketTest.java isn't running because @test
is taken away when we backport JDK-8225690. we try to keep the patch
intact in case we enable it in the future.
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@phohensee phohensee left a comment

Lgtm.

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@openjdk openjdk bot commented Apr 6, 2022

@navyxliu This change now passes all automated pre-integration checks.

After integration, the commit message for the final commit will be:

8235211: serviceability/attach/RemovingUnixDomainSocketTest.java fails with AttachNotSupportedException: Unable to open socket file
8244973: serviceability/attach/RemovingUnixDomainSocketTest.java fails "stderr was not empty"

Reviewed-by: phh, andrew

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 35 new commits pushed to the master branch:

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

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@openjdk openjdk bot added the ready label Apr 6, 2022
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@navyxliu This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply add a new comment to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

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@gnu-andrew gnu-andrew left a comment

Looks good to me. Clean backport bar the naked_yield/yield change.

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@gnu-andrew gnu-andrew commented May 9, 2022

Added jdk8u-fix-yes.

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@navyxliu navyxliu commented May 9, 2022

/integrate

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@openjdk openjdk bot commented May 9, 2022

@navyxliu
Your change (at version 6f86e09) is now ready to be sponsored by a Committer.

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@phohensee phohensee commented May 9, 2022

/sponsor

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@openjdk openjdk bot commented May 9, 2022

Going to push as commit 1067c54.
Since your change was applied there have been 35 commits pushed to the master branch:

Your commit was automatically rebased without conflicts.

@openjdk openjdk bot added the integrated label May 9, 2022
@openjdk openjdk bot closed this May 9, 2022
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@openjdk openjdk bot commented May 9, 2022

@phohensee @navyxliu Pushed as commit 1067c54.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

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