[
https://issues.apache.org/jira/browse/SLING-7447?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Robert Munteanu updated SLING-7447:
-----------------------------------
Description:
There is a race condition in the {{ThreadLocalCleaner}} initialization code
that can lead to the fields not being fully initialized when read.
The stack trace is similar to
{noformat}Exception in thread "sling-oak-observation-2"
java.lang.NullPointerException
at
org.apache.sling.commons.threads.impl.ThreadLocalCleaner.copy(ThreadLocalCleaner.java:110)
at
org.apache.sling.commons.threads.impl.ThreadLocalCleaner.saveOldThreadLocals(ThreadLocalCleaner.java:230)
at
org.apache.sling.commons.threads.impl.ThreadLocalCleaner.<init>(ThreadLocalCleaner.java:155)
at
org.apache.sling.commons.threads.impl.ThreadPoolExecutorCleaningThreadLocals.beforeExecute(ThreadPoolExecutorCleaningThreadLocals.java:58)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1139)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:748){noformat}
Assume that two threads, _T1_ and _T2_ enter the constructor at more or less
the same time. The following events can then occur, leading to the above
invalid access
||T1||T2||
|check threadLocalsField (is null)| |
|invoke initReflectionFields, load threadLocalsField| |
| | check threadLocalsField (is not null) |
| | invoke saveOldTreadLocals |
| | invoke copy |
At this point, the {{tableField}} field is null since {{initReflectionFields}}
has not yet completed, which leads to the above NPE.
_edit_: formatting
was:
There is a race condition in the {{ThreadLocalCleaner}} initialization code
that can lead to the fields not being fully initialized when read.
The stack trace is similar to
{noformat}Exception in thread "sling-oak-observation-2"
java.lang.NullPointerException
at
org.apache.sling.commons.threads.impl.ThreadLocalCleaner.copy(ThreadLocalCleaner.java:110)
at
org.apache.sling.commons.threads.impl.ThreadLocalCleaner.saveOldThreadLocals(ThreadLocalCleaner.java:230)
at
org.apache.sling.commons.threads.impl.ThreadLocalCleaner.<init>(ThreadLocalCleaner.java:155)
at
org.apache.sling.commons.threads.impl.ThreadPoolExecutorCleaningThreadLocals.beforeExecute(ThreadPoolExecutorCleaningThreadLocals.java:58)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1139)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:748){noformat}
Assume that two threads, _T1_ and _T2_ enter the constructor at more or less
the same time. The following events can then occur, leading to the above
invalid access
||T1||T2||
|check threadLocalsField (is null)| - |
|invoke initReflectionFields, load threadLocalsField| - |
| - | check threadLocalsField (is not null) |
| - | invoke saveOldTreadLocals |
| - | invoke copy |
At this point, the {{tableField}} field is null since {{initReflectionFields}}
has not yet completed, which leads to the above NPE.
> Race condition in ThreadLocalCleaner initialization code
> --------------------------------------------------------
>
> Key: SLING-7447
> URL: https://issues.apache.org/jira/browse/SLING-7447
> Project: Sling
> Issue Type: Bug
> Components: Commons
> Affects Versions: Commons Threads 3.2.14
> Reporter: Robert Munteanu
> Assignee: Robert Munteanu
> Priority: Blocker
> Fix For: Commons Threads 3.2.16
>
>
> There is a race condition in the {{ThreadLocalCleaner}} initialization code
> that can lead to the fields not being fully initialized when read.
> The stack trace is similar to
> {noformat}Exception in thread "sling-oak-observation-2"
> java.lang.NullPointerException
> at
> org.apache.sling.commons.threads.impl.ThreadLocalCleaner.copy(ThreadLocalCleaner.java:110)
> at
> org.apache.sling.commons.threads.impl.ThreadLocalCleaner.saveOldThreadLocals(ThreadLocalCleaner.java:230)
> at
> org.apache.sling.commons.threads.impl.ThreadLocalCleaner.<init>(ThreadLocalCleaner.java:155)
> at
> org.apache.sling.commons.threads.impl.ThreadPoolExecutorCleaningThreadLocals.beforeExecute(ThreadPoolExecutorCleaningThreadLocals.java:58)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1139)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:748){noformat}
> Assume that two threads, _T1_ and _T2_ enter the constructor at more or less
> the same time. The following events can then occur, leading to the above
> invalid access
> ||T1||T2||
> |check threadLocalsField (is null)| |
> |invoke initReflectionFields, load threadLocalsField| |
> | | check threadLocalsField (is not null) |
> | | invoke saveOldTreadLocals |
> | | invoke copy |
> At this point, the {{tableField}} field is null since
> {{initReflectionFields}} has not yet completed, which leads to the above NPE.
> _edit_: formatting
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