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Warnings reported with -Xcheck:jni when using Memory class

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
25/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Stale
Tech stack
java
Domain
operating-systems

Research direction

Reproduce the report with the supplied Java snippet, OpenJDK 11.0.8, JNA 5.6.0, and -Xcheck:jni. Start by tracing Native.loadNativeDispatchLibraryFromClasspath and Memory.malloc in Native.java and Memory.java; done means determining whether the reported JNI warnings can be eliminated and covering the result with a regression test.

Written by the indexing model from the issue text.

Description

To reproduce, run the following snippet with -Xcheck:jni VM argument (I'm running with OpenJDK 11.0.8):

import com.sun.jna.Memory;

public class Test {

	public static void main(String[] args) {
		Memory m = new Memory(1024L);
		System.out.println(m);
	}

}

Observe output:

Warning: SIGINT handler expected:libjvm.so+0xc14f00  found:0x0000000000000001
Running in non-interactive shell, SIGINT handler is replaced by shell
Signal Handlers:
SIGSEGV: [libjvm.so+0xc14d00], sa_mask[0]=11111111011111111101111111111110, sa_flags=SA_RESTART|SA_SIGINFO
SIGBUS: [libjvm.so+0xc14d00], sa_mask[0]=11111111011111111101111111111110, sa_flags=SA_RESTART|SA_SIGINFO
SIGFPE: [libjvm.so+0xc14d00], sa_mask[0]=11111111011111111101111111111110, sa_flags=SA_RESTART|SA_SIGINFO
SIGPIPE: [libjvm.so+0xc14d00], sa_mask[0]=11111111011111111101111111111110, sa_flags=SA_RESTART|SA_SIGINFO
SIGXFSZ: [libjvm.so+0xc14d00], sa_mask[0]=11111111011111111101111111111110, sa_flags=SA_RESTART|SA_SIGINFO
SIGILL: [libjvm.so+0xc14d00], sa_mask[0]=11111111011111111101111111111110, sa_flags=SA_RESTART|SA_SIGINFO
SIGUSR2: [libjvm.so+0xc14b80], sa_mask[0]=00100000000000000000000000000000, sa_flags=SA_RESTART|SA_SIGINFO
SIGHUP: [libjvm.so+0xc14f00], sa_mask[0]=11111111011111111101111111111110, sa_flags=SA_RESTART|SA_SIGINFO
SIGINT: SIG_IGN, sa_mask[0]=00000000000000000000000000000000, sa_flags=none
SIGTERM: [libjvm.so+0xc14f00], sa_mask[0]=11111111011111111101111111111110, sa_flags=SA_RESTART|SA_SIGINFO
SIGQUIT: [libjvm.so+0xc14f00], sa_mask[0]=11111111011111111101111111111110, sa_flags=SA_RESTART|SA_SIGINFO
WARNING: JNI local refs: 33, exceeds capacity: 32
	at java.lang.ClassLoader$NativeLibrary.load0([email protected]/Native Method)
	at java.lang.ClassLoader$NativeLibrary.load([email protected]/ClassLoader.java:2442)
	at java.lang.ClassLoader$NativeLibrary.loadLibrary([email protected]/ClassLoader.java:2498)
	- locked <0x00000000ff401e20> (a java.util.HashSet)
	at java.lang.ClassLoader.loadLibrary0([email protected]/ClassLoader.java:2694)
	at java.lang.ClassLoader.loadLibrary([email protected]/ClassLoader.java:2627)
	at java.lang.Runtime.load0([email protected]/Runtime.java:768)
	at java.lang.System.load([email protected]/System.java:1837)
	at com.sun.jna.Native.loadNativeDispatchLibraryFromClasspath(Native.java:1018)
	at com.sun.jna.Native.loadNativeDispatchLibrary(Native.java:988)
	at com.sun.jna.Native.<clinit>(Native.java:195)
	at com.sun.jna.Memory.malloc(Memory.java:722)
	at com.sun.jna.Memory.<init>(Memory.java:114)
	at test.Test.main(Test.java:9)
WARNING in native method: JNI call made without checking exceptions when required to from CallStaticObjectMethod
	at java.lang.ClassLoader$NativeLibrary.load0([email protected]/Native Method)
	at java.lang.ClassLoader$NativeLibrary.load([email protected]/ClassLoader.java:2442)
	at java.lang.ClassLoader$NativeLibrary.loadLibrary([email protected]/ClassLoader.java:2498)
	- locked <0x00000000ff401e20> (a java.util.HashSet)
	at java.lang.ClassLoader.loadLibrary0([email protected]/ClassLoader.java:2694)
	at java.lang.ClassLoader.loadLibrary([email protected]/ClassLoader.java:2627)
	at java.lang.Runtime.load0([email protected]/Runtime.java:768)
	at java.lang.System.load([email protected]/System.java:1837)
	at com.sun.jna.Native.loadNativeDispatchLibraryFromClasspath(Native.java:1018)
	at com.sun.jna.Native.loadNativeDispatchLibrary(Native.java:988)
	at com.sun.jna.Native.<clinit>(Native.java:195)
	at com.sun.jna.Memory.malloc(Memory.java:722)
	at com.sun.jna.Memory.<init>(Memory.java:114)
	at test.Test.main(Test.java:9)
allocated@0x7ffff0510730 (1024 bytes)

Seen with jna-5.6.0.jar (latest I could find from maven: https://mvnrepository.com/artifact/net.java.dev.jna/jna).

Background:

We observe those warnings in our Eclipse based product (when checking for JNI problems with -Xcheck:jni), coming from SVN plug-ins:

WARNING in native method: JNI call made without checking exceptions when required to from CallStaticObjectMethod
	at java.lang.ClassLoader$NativeLibrary.load0([email protected]/Native Method)
	at java.lang.ClassLoader$NativeLibrary.load([email protected]/ClassLoader.java:2442)
	at java.lang.ClassLoader$NativeLibrary.loadLibrary([email protected]/ClassLoader.java:2498)
	- locked <0x00000005007d6730> (a java.util.HashSet)
	at java.lang.ClassLoader.loadLibrary0([email protected]/ClassLoader.java:2694)
	at java.lang.ClassLoader.loadLibrary([email protected]/ClassLoader.java:2627)
	at java.lang.Runtime.load0([email protected]/Runtime.java:768)
	at java.lang.System.load([email protected]/System.java:1837)
	at com.sun.jna.Native.loadNativeDispatchLibraryFromClasspath(Native.java:761)
	at com.sun.jna.Native.loadNativeDispatchLibrary(Native.java:736)
	at com.sun.jna.Native.<clinit>(Native.java:131)
	at com.sun.jna.Pointer.<clinit>(Pointer.java:41)
	at org.tmatesoft.svn.core.internal.util.jna.SVNLinuxUtil.<clinit>(SVNLinuxUtil.java:33)
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