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8282947: JFR: Dump on shutdown live-locks in some conditions
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Reviewed-by: mgronlun
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egahlin committed May 27, 2022
1 parent f2bc447 commit 63eb0b7
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Showing 3 changed files with 65 additions and 4 deletions.
7 changes: 5 additions & 2 deletions src/jdk.jfr/share/classes/jdk/jfr/internal/ChunksChannel.java
Expand Up @@ -96,10 +96,13 @@ public long transferTo(FileChannel out) throws IOException {
assert current != null;

long rem = current.getSize();

while (rem > 0) {
long n = Math.min(rem, 1024 * 1024);
long w = out.transferFrom(channel, pos, n);
// Prevent endless loop
if (w == 0) {
return out.size();
}
pos += w;
rem -= w;
}
Expand All @@ -111,7 +114,7 @@ public long transferTo(FileChannel out) throws IOException {
current = null;
}
if (!nextChannel()) {
return pos;
return out.size();
}
}
}
Expand Down
Expand Up @@ -713,8 +713,12 @@ public void dumpStopped(WriteableUserPath userPath) throws IOException {
synchronized (recorder) {
userPath.doPrivilegedIO(() -> {
try (ChunksChannel cc = new ChunksChannel(chunks); FileChannel fc = FileChannel.open(userPath.getReal(), StandardOpenOption.WRITE, StandardOpenOption.APPEND)) {
cc.transferTo(fc);
fc.force(true);
long bytes = cc.transferTo(fc);
Logger.log(LogTag.JFR, LogLevel.INFO, "Transferred " + bytes + " bytes from the disk repository");
// No need to force if no data was transferred, which avoids IOException when device is /dev/null
if (bytes != 0) {
fc.force(true);
}
}
return null;
});
Expand Down
54 changes: 54 additions & 0 deletions test/jdk/jdk/jfr/api/recording/dump/TestDumpDevNull.java
@@ -0,0 +1,54 @@
/*
* Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/

package jdk.jfr.api.recording.dump;

import java.nio.file.Path;

import jdk.jfr.Recording;

/**
* @test
* @summary Tests that it's possible to dump to /dev/null without a livelock
* @key jfr
* @requires vm.hasJFR
* @library /test/lib
* @run main/othervm -Xlog:jfr jdk.jfr.api.recording.dump.TestDumpDevNull
*/
public class TestDumpDevNull {

public static void main(String[] args) throws Exception {
try (Recording r1 = new Recording()) {
r1.setDestination(Path.of("/dev/null"));
r1.start();
// Force a chunk rotation which ensures that jdk.jfr.internal.ChunkChannel
// invokes FileChannel::transferFrom(ReadableByteChannel, position, count) twice.
// FileChannel will return 0 the second time because position exceeds
// FileChannel::size(), which is always 0 for /dev/null
// Without proper handling of return value 0, the ChunkChannel will spin indefinitely.
try (Recording r2 = new Recording()) {
r2.start();
}
}
}
}

11 comments on commit 63eb0b7

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/backport jdk18u

@openjdk
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@openjdk openjdk bot commented on 63eb0b7 Jun 7, 2022

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@judovana the backport was successfully created on the branch judovana-backport-63eb0b7e in my personal fork of openjdk/jdk18u. To create a pull request with this backport targeting openjdk/jdk18u:master, just click the following link:

➡️ Create pull request

The title of the pull request is automatically filled in correctly and below you find a suggestion for the pull request body:

Hi all,

This pull request contains a backport of commit 63eb0b7e from the openjdk/jdk repository.

The commit being backported was authored by Erik Gahlin on 27 May 2022 and was reviewed by Markus Grönlund.

Thanks!

If you need to update the source branch of the pull then run the following commands in a local clone of your personal fork of openjdk/jdk18u:

$ git fetch https://github.com/openjdk-bots/jdk18u judovana-backport-63eb0b7e:judovana-backport-63eb0b7e
$ git checkout judovana-backport-63eb0b7e
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk18u judovana-backport-63eb0b7e

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/backport jdk17u

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@openjdk openjdk bot commented on 63eb0b7 Jul 14, 2022

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@judovana the backport was successfully created on the branch judovana-backport-63eb0b7e in my personal fork of openjdk/jdk17u. To create a pull request with this backport targeting openjdk/jdk17u:master, just click the following link:

➡️ Create pull request

The title of the pull request is automatically filled in correctly and below you find a suggestion for the pull request body:

Hi all,

This pull request contains a backport of commit 63eb0b7e from the openjdk/jdk repository.

The commit being backported was authored by Erik Gahlin on 27 May 2022 and was reviewed by Markus Grönlund.

Thanks!

If you need to update the source branch of the pull then run the following commands in a local clone of your personal fork of openjdk/jdk17u:

$ git fetch https://github.com/openjdk-bots/jdk17u judovana-backport-63eb0b7e:judovana-backport-63eb0b7e
$ git checkout judovana-backport-63eb0b7e
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk17u judovana-backport-63eb0b7e

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/backport jdk17u-dev

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@openjdk openjdk bot commented on 63eb0b7 Jul 15, 2022

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@judovana the backport was successfully created on the branch judovana-backport-63eb0b7e in my personal fork of openjdk/jdk17u-dev. To create a pull request with this backport targeting openjdk/jdk17u-dev:master, just click the following link:

➡️ Create pull request

The title of the pull request is automatically filled in correctly and below you find a suggestion for the pull request body:

Hi all,

This pull request contains a backport of commit 63eb0b7e from the openjdk/jdk repository.

The commit being backported was authored by Erik Gahlin on 27 May 2022 and was reviewed by Markus Grönlund.

Thanks!

If you need to update the source branch of the pull then run the following commands in a local clone of your personal fork of openjdk/jdk17u-dev:

$ git fetch https://github.com/openjdk-bots/jdk17u-dev judovana-backport-63eb0b7e:judovana-backport-63eb0b7e
$ git checkout judovana-backport-63eb0b7e
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk17u-dev judovana-backport-63eb0b7e

@judovana
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/backport jdk11u-dev

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@openjdk openjdk bot commented on 63eb0b7 Aug 19, 2022

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@judovana the backport was successfully created on the branch judovana-backport-63eb0b7e in my personal fork of openjdk/jdk11u-dev. To create a pull request with this backport targeting openjdk/jdk11u-dev:master, just click the following link:

➡️ Create pull request

The title of the pull request is automatically filled in correctly and below you find a suggestion for the pull request body:

Hi all,

This pull request contains a backport of commit 63eb0b7e from the openjdk/jdk repository.

The commit being backported was authored by Erik Gahlin on 27 May 2022 and was reviewed by Markus Grönlund.

Thanks!

If you need to update the source branch of the pull then run the following commands in a local clone of your personal fork of openjdk/jdk11u-dev:

$ git fetch https://github.com/openjdk-bots/jdk11u-dev judovana-backport-63eb0b7e:judovana-backport-63eb0b7e
$ git checkout judovana-backport-63eb0b7e
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk11u-dev judovana-backport-63eb0b7e

@judovana
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/backport jdk8u-dev

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@openjdk openjdk bot commented on 63eb0b7 Jan 19, 2023

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@judovana Could not automatically backport 63eb0b7e to openjdk/jdk8u-dev due to conflicts in the following files:

  • jdk/test/jdk/jfr/recording/dump/TestDumpDevNull.java

Please fetch the appropriate branch/commit and manually resolve these conflicts by using the following commands in your personal fork of openjdk/jdk8u-dev. Note: these commands are just some suggestions and you can use other equivalent commands you know.

# Fetch the up-to-date version of the target branch
$ git fetch --no-tags https://git.openjdk.org/jdk8u-dev master:master

# Check out the target branch and create your own branch to backport
$ git checkout master
$ git checkout -b judovana-backport-63eb0b7e

# Fetch the commit you want to backport
$ git fetch --no-tags https://git.openjdk.org/jdk 63eb0b7e8606dd9cd145e92eeeb744ff5b7be569

# Backport the commit
$ git cherry-pick --no-commit 63eb0b7e8606dd9cd145e92eeeb744ff5b7be569
# Resolve conflicts now

# Commit the files you have modified
$ git add files/with/resolved/conflicts
$ git commit -m 'Backport 63eb0b7e8606dd9cd145e92eeeb744ff5b7be569'

Once you have resolved the conflicts as explained above continue with creating a pull request towards the openjdk/jdk8u-dev with the title Backport 63eb0b7e8606dd9cd145e92eeeb744ff5b7be569.

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