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https://issues.apache.org/jira/browse/HADOOP-18217?focusedWorklogId=764920&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-764920
]
ASF GitHub Bot logged work on HADOOP-18217:
-------------------------------------------
Author: ASF GitHub Bot
Created on: 02/May/22 12:47
Start Date: 02/May/22 12:47
Worklog Time Spent: 10m
Work Description: hadoop-yetus commented on PR #4255:
URL: https://github.com/apache/hadoop/pull/4255#issuecomment-1114806690
:broken_heart: **-1 overall**
| Vote | Subsystem | Runtime | Logfile | Comment |
|:----:|----------:|--------:|:--------:|:-------:|
| +0 :ok: | reexec | 17m 59s | | Docker mode activated. |
|||| _ Prechecks _ |
| +1 :green_heart: | dupname | 0m 0s | | No case conflicting files
found. |
| +0 :ok: | codespell | 0m 1s | | codespell was not available. |
| +1 :green_heart: | @author | 0m 0s | | The patch does not contain
any @author tags. |
| -1 :x: | test4tests | 0m 1s | | The patch doesn't appear to include
any new or modified tests. Please justify why no new tests are needed for this
patch. Also please list what manual steps were performed to verify this patch.
|
|||| _ trunk Compile Tests _ |
| +1 :green_heart: | mvninstall | 41m 26s | | trunk passed |
| +1 :green_heart: | compile | 25m 9s | | trunk passed with JDK
Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1 |
| +1 :green_heart: | compile | 21m 50s | | trunk passed with JDK
Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07 |
| +1 :green_heart: | checkstyle | 1m 45s | | trunk passed |
| +1 :green_heart: | mvnsite | 2m 7s | | trunk passed |
| -1 :x: | javadoc | 1m 38s |
[/branch-javadoc-hadoop-common-project_hadoop-common-jdkPrivateBuild-11.0.15+10-Ubuntu-0ubuntu0.20.04.1.txt](https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4255/1/artifact/out/branch-javadoc-hadoop-common-project_hadoop-common-jdkPrivateBuild-11.0.15+10-Ubuntu-0ubuntu0.20.04.1.txt)
| hadoop-common in trunk failed with JDK Private
Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1. |
| +1 :green_heart: | javadoc | 2m 9s | | trunk passed with JDK
Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07 |
| +1 :green_heart: | spotbugs | 3m 24s | | trunk passed |
| +1 :green_heart: | shadedclient | 27m 18s | | branch has no errors
when building and testing our client artifacts. |
|||| _ Patch Compile Tests _ |
| +1 :green_heart: | mvninstall | 1m 10s | | the patch passed |
| +1 :green_heart: | compile | 24m 2s | | the patch passed with JDK
Private Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1 |
| +1 :green_heart: | javac | 24m 2s | | the patch passed |
| +1 :green_heart: | compile | 21m 36s | | the patch passed with JDK
Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07 |
| +1 :green_heart: | javac | 21m 36s | | the patch passed |
| +1 :green_heart: | blanks | 0m 0s | | The patch has no blanks
issues. |
| -0 :warning: | checkstyle | 1m 23s |
[/results-checkstyle-hadoop-common-project_hadoop-common.txt](https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4255/1/artifact/out/results-checkstyle-hadoop-common-project_hadoop-common.txt)
| hadoop-common-project/hadoop-common: The patch generated 3 new + 2
unchanged - 0 fixed = 5 total (was 2) |
| +1 :green_heart: | mvnsite | 1m 55s | | the patch passed |
| -1 :x: | javadoc | 1m 26s |
[/patch-javadoc-hadoop-common-project_hadoop-common-jdkPrivateBuild-11.0.15+10-Ubuntu-0ubuntu0.20.04.1.txt](https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4255/1/artifact/out/patch-javadoc-hadoop-common-project_hadoop-common-jdkPrivateBuild-11.0.15+10-Ubuntu-0ubuntu0.20.04.1.txt)
| hadoop-common in the patch failed with JDK Private
Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1. |
| +1 :green_heart: | javadoc | 1m 59s | | the patch passed with JDK
Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07 |
| +1 :green_heart: | spotbugs | 3m 1s | | the patch passed |
| +1 :green_heart: | shadedclient | 25m 37s | | patch has no errors
when building and testing our client artifacts. |
|||| _ Other Tests _ |
| +1 :green_heart: | unit | 18m 8s | | hadoop-common in the patch
passed. |
| +1 :green_heart: | asflicense | 1m 13s | | The patch does not
generate ASF License warnings. |
| | | 246m 22s | | |
| Subsystem | Report/Notes |
|----------:|:-------------|
| Docker | ClientAPI=1.41 ServerAPI=1.41 base:
https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4255/1/artifact/out/Dockerfile
|
| GITHUB PR | https://github.com/apache/hadoop/pull/4255 |
| Optional Tests | dupname asflicense compile javac javadoc mvninstall
mvnsite unit shadedclient spotbugs checkstyle codespell |
| uname | Linux 0b98321b98d7 4.15.0-175-generic #184-Ubuntu SMP Thu Mar 24
17:48:36 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | dev-support/bin/hadoop.sh |
| git revision | trunk / 55b71c8b9bf2840f3bae05c97703eb2c08672b58 |
| Default Java | Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07 |
| Multi-JDK versions | /usr/lib/jvm/java-11-openjdk-amd64:Private
Build-11.0.15+10-Ubuntu-0ubuntu0.20.04.1
/usr/lib/jvm/java-8-openjdk-amd64:Private
Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07 |
| Test Results |
https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4255/1/testReport/ |
| Max. process+thread count | 2019 (vs. ulimit of 5500) |
| modules | C: hadoop-common-project/hadoop-common U:
hadoop-common-project/hadoop-common |
| Console output |
https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4255/1/console |
| versions | git=2.25.1 maven=3.6.3 spotbugs=4.2.2 |
| Powered by | Apache Yetus 0.14.0-SNAPSHOT https://yetus.apache.org |
This message was automatically generated.
Issue Time Tracking
-------------------
Worklog Id: (was: 764920)
Time Spent: 0.5h (was: 20m)
> shutdownhookmanager should not be multithreaded (deadlock possible)
> -------------------------------------------------------------------
>
> Key: HADOOP-18217
> URL: https://issues.apache.org/jira/browse/HADOOP-18217
> Project: Hadoop Common
> Issue Type: Bug
> Components: util
> Affects Versions: 2.10.1
> Environment: linux, windows, any version
> Reporter: Catherinot Remi
> Priority: Minor
> Labels: pull-request-available
> Attachments: wtf.java
>
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> the ShutdownHookManager class uses an executor to run hooks to have a
> "timeout" notion around them. It does this using a single threaded executor.
> It can leads to deadlock leaving a never-shutting-down JVM with this
> execution flow:
> * JVM need to exit (only daemon threads remaining or someone called
> System.exit)
> * ShutdowHookManager kicks in
> * SHMngr executor start running some hooks
> * SHMngr executor thread kicks in and, as a side effect, run some code from
> one of the hook that calls System.exit (as a side effect from an external lib
> for example)
> * the executor thread is waiting for a lock because another thread already
> entered System.exit and has its internal lock, so the executor never returns.
> * SHMngr never returns
> * 1st call to System.exit never returns
> * JVM stuck
>
> using an executor with a single thread does "fake" timeouts (the task keeps
> running, you can interrupt it but until it stumble upon some piece of code
> that is interruptible (like an IO) it will keep running) especially since the
> executor is a single threaded one. So it has this bug for example :
> * caller submit 1st hook (bad one that would need 1 hour of runtime and that
> cannot be interrupted)
> * executor start 1st hook
> * caller of the future 1st hook result timeout
> * caller submit 2nd hook
> * bug : 1 hook still running, 2nd hook triggers a timeout but never got the
> chance to run anyway, so 1st faulty hook makes it impossible for any other
> hook to have a chance to run, so running hooks in a single separate thread
> does not allow to run other hooks in parallel to long ones.
>
> If we really really want to timeout the JVM shutdown, even accepting maybe
> dirty shutdown, it should rather handle the hooks inside the initial thread
> (not spawning new one(s) so not triggering the deadlock described on the 1st
> place) and if a timeout was configured, only spawn a single parallel daemon
> thread that sleeps the timeout delay, and then use Runtime.halt (which bypass
> the hook system so should not trigger the deadlock). If the normal
> System.exit ends before the timeout delay everything is fine. If the
> System.exit took to much time, the JVM is killed and so the reason why this
> multithreaded shutdown hook implementation was created is satisfied (avoding
> having hanging JVMs)
>
> Had the bug with both oracle and open jdk builds, all in 1.8 major version.
> hadoop 2.6 and 2.7 did not have the issue because they do not run hooks in
> another thread
>
> Another solution is of course to configure the timeout AND to have as many
> threads as needed to run the hooks so to have at least some gain to offset
> the pain of the dealock scenario
>
> EDIT: added some logs and reproduced the problem. in fact it is located after
> triggering all the hook entries and before shutting down the executor.
> Current code, after running the hooks, creates a new Configuration object and
> reads the configured timeout from it, applies this timeout to shutdown the
> executor. I sometimes run with a classloader doing remote classloading,
> Configuration loads its content using this classloader, so when shutting down
> the JVM and some network error occurs the classloader fails to load the
> ressources needed by Configuration. So the code crash before shutting down
> the executor and ends up inside the thread's default uncaught throwable
> handler, which was calling System.exit, so got stuck, so shutting down the
> executor never returned, so does the JVM.
> So, forget about the halt stuff (even if it is a last ressort very robust
> safety net). Still I'll do a small adjustement to the final executor shutdown
> code to be slightly more robust to even the strangest exceptions/errors it
> encounters.
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