When using the xgboost4j 1.7.6 version, a core dump occasionally occurs, with an error reported when releasing the XGDMatrix object. How to resolve it? Is it a known issue?

[zhuyakui680]

[trivialfis]

No, it's not a known issue. One guess is you are running into race condition with DMatrix.

[zhuyakui680]

No, it's not a known issue. One guess is you are running into race condition with DMatrix.

key word 'DMatrix' is not found in my code, i guess repeated memory free may occurs in xgboost code.

[trivialfis]

i guess repeated memory free may occurs in xgboost code.

I don't see how this can happen with the finalize method and the dispose method that it calls:

xgboost/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/DMatrix.java

Line 504 in c50e81d

protected void finalize() {

Feel free to point out potential issues.

key word 'DMatrix' is not found in my code,

Could you please share how you use XGBoost?

My race condition guess is simply based on your description that something happens occasionally instead of deterministically. If you can provide more information, such as a way to reproduce the issue cleanly with only XGBoost, I can help look into it.

[zhuyakui680]

i guess repeated memory free may occurs in xgboost code.

I don't see how this can happen with the finalize method and the dispose method that it calls:

xgboost/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/DMatrix.java

Line 504 in c50e81d

protected void finalize() {
Feel free to point out potential issues.

key word 'DMatrix' is not found in my code,

Could you please share how you use XGBoost?

My race condition guess is simply based on your description that something happens occasionally instead of deterministically. If you can provide more information, such as a way to reproduce the issue cleanly with only XGBoost, I can help look into it.

Is it possible for a DMatrix object, after being garbage collected by the Java memory mechanism (garbage collection mechanism), to be double-freed by XGBoost code, leading to issues caused by "dangling pointers"?

[trivialfis]

No, the only way to free the DMatrix is by calling the XGDMatrixFree. For the Java interface, this function is wrapped into the dispose method, which the GC calls.