Race condition on concurrent ApplicationContext start [3.10.x] #10091
Comments
WorkaroundCall The root cause
ConvertiblePair pair = new ConvertiblePair(sourceType, targetType, null);
// Some thread gets null for 'micronaut.server.cors.enabled' because converterCache has been reset by other thread
TypeConverter typeConverter = converterCache.get(pair); // line 144
if (typeConverter == null) {
// Also gets null here
typeConverter = findTypeConverter(sourceType, targetType, null);
if (typeConverter == null) {
// Puts UNCONVERTIBLE into the converter cache
// So, another thread reads this value from the cache on the line 144
// This causes the error
converterCache.put(pair, UNCONVERTIBLE);
return Optional.empty();
} else {
converterCache.put(pair, typeConverter);
if (typeConverter == UNCONVERTIBLE) {
return Optional.empty();
} else {
return typeConverter.convert(object, targetType, context);
}
}Here is how protected <T> TypeConverter findTypeConverter(Class<?> sourceType, Class<T> targetType, String formattingAnnotation) {
TypeConverter typeConverter = UNCONVERTIBLE;
List<Class> sourceHierarchy = ClassUtils.resolveHierarchy(sourceType);
List<Class> targetHierarchy = ClassUtils.resolveHierarchy(targetType);
for (Class sourceSuperType : sourceHierarchy) {
for (Class targetSuperType : targetHierarchy) {
ConvertiblePair pair = new ConvertiblePair(sourceSuperType, targetSuperType, formattingAnnotation);
// it gets in from here because there is a small amount of time when typeConverters are empty
typeConverter = typeConverters.get(pair);
if (typeConverter != null) {
converterCache.put(pair, typeConverter);
return typeConverter;
}
}
}Here is what happening on the application context start in if (initializing.compareAndSet(false, true)) {
// Reset possibly modified shared context
((DefaultConversionService) ConversionService.SHARED).reset(); // <- HERE shared caches a reseted on each startLooking at the public void reset() {
typeConverters.clear(); // thread 1 exec this
converterCache.clear(); // thread 1 sleep here
registerDefaultConverters();
}
// thread 2 gets null typeConverters.get('micronaut.server.cors.enabled')
// thread 2 puts 'micronaut.server.cors.enabled' = UNCONVERTIBLE into converterCache
// any other thread can read the UNCONVERTIVLE value from converterCacheProposed fixUse global shared lock for the |
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I know that the I would like to contribute a fix for the issue in 3.10.x branch. @dstepanov I saw your changes in the codebase, WDYT? |
It happens bacause of the race condition inside micronaut. micronaut-projects/micronaut-core#10091
It happens because of the race conditions inside the micronaut. micronaut-projects/micronaut-core#10091
It happens because of the race conditions inside the micronaut. micronaut-projects/micronaut-core#10091
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@PakhomovAlexander Do you have a solution in mind for this? I'm not confident locking on the ping @dstepanov do you have some thoughts about this? I have created a reproducible example project with the code provided in the description at https://github.com/wetted/core-10091-race-condition. |
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@wetted thanks for your response. I found a benchmark |
wetted
added
the
status: validated
Expected Behavior
Concurrent calls for
Micronaut#start()will launch multiple servers without errors.Actual Behaviour
The code in
Steps To Reproducepart sometimes fails with the output into stderr:Steps To Reproduce
Environment Information
java version "17.0.8" 2023-07-18 LTSExample Application
No response
Version
3.10.x
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