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Use ReentrantLock instead of synchronized in DeserializerCache to avoid deadlock on pinning #4430

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Merged
merged 4 commits into from
Mar 29, 2024
Merged

Use ReentrantLock instead of synchronized in DeserializerCache to avoid deadlock on pinning #4430

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48124cd
Use ReentrantLock instead of synchronized to avoid deadlock on pinning
oddbjornkvalsund Mar 13, 2024
2668e5f
Replace most usage of synchronized with ReentrantLock
oddbjornkvalsund Mar 15, 2024
43a2e8a
Merge branch '2.17' into 2.17
cowtowncoder Mar 28, 2024
d512683
Revert "Replace most usage of synchronized with ReentrantLock"
oddbjornkvalsund Mar 29, 2024
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13 changes: 12 additions & 1 deletion src/main/java/com/fasterxml/jackson/databind/deser/DeserializerCache.java
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
package com.fasterxml.jackson.databind.deser;

import java.util.HashMap;
import java.util.concurrent.locks.ReentrantLock;

import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.databind.*;
Expand Down Expand Up @@ -52,6 +53,12 @@ public final class DeserializerCache
protected final HashMap<JavaType, JsonDeserializer<Object>> _incompleteDeserializers
= new HashMap<JavaType, JsonDeserializer<Object>>(8);


/**
* We hold an explicit lock while creating deserializers to avoid creating duplicates.
*/
private final ReentrantLock _incompleteDeserializersLock = new ReentrantLock();

/*
/**********************************************************
/* Life-cycle
Expand Down Expand Up @@ -246,7 +253,9 @@ protected JsonDeserializer<Object> _createAndCacheValueDeserializer(Deserializat
* limitations necessary to ensure that only completely initialized ones
* are visible and used.
*/
synchronized (_incompleteDeserializers) {
try {
_incompleteDeserializersLock.lock();

// Ok, then: could it be that due to a race condition, deserializer can now be found?
JsonDeserializer<Object> deser = _findCachedDeserializer(type);
if (deser != null) {
Expand All @@ -269,6 +278,8 @@ protected JsonDeserializer<Object> _createAndCacheValueDeserializer(Deserializat
_incompleteDeserializers.clear();
}
}
} finally {
_incompleteDeserializersLock.unlock();
}
}

Expand Down