[HADOOP-10027] *Compressor_deflateBytesDirect passes instance instead of jclass to GetStaticObjectField

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Component/s: native
• Target Version/s: 2.8.0
• Hadoop Flags: Reviewed
• Assignee: Hui Zheng
• Reporter: Eric Abbott
• Created: 07/Oct/13 15:26
• Updated: 30/Aug/16 01:32
• Resolved: 12/Mar/15 06:47

Description

http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-common-project/hadoop-common/src/main/native/src/org/apache/hadoop/io/compress/zlib/ZlibCompressor.c?view=markup

This pattern appears in all the native compressors.
// Get members of ZlibCompressor
jobject clazz = (*env)->GetStaticObjectField(env, this,
ZlibCompressor_clazz);

The 2nd argument to GetStaticObjectField is supposed to be a jclass, not a jobject. Adding the JVM param -Xcheck:jni will cause "FATAL ERROR in native method: JNI received a class argument that is not a class" and a core dump such as the following.

(gdb)
#0 0x00007f02e4aef8a5 in raise () from /lib64/libc.so.6
#1 0x00007f02e4af1085 in abort () from /lib64/libc.so.6
#2 0x00007f02e45bd727 in os::abort(bool) () from /opt/jdk1.6.0_31/jre/lib/amd64/server/libjvm.so
#3 0x00007f02e43cec63 in jniCheck::validate_class(JavaThread*, _jclass*, bool) () from /opt/jdk1.6.0_31/jre/lib/amd64/server/libjvm.so
#4 0x00007f02e43ea669 in checked_jni_GetStaticObjectField () from /opt/jdk1.6.0_31/jre/lib/amd64/server/libjvm.so
#5 0x00007f02d38eaf79 in Java_org_apache_hadoop_io_compress_zlib_ZlibCompressor_deflateBytesDirect () from /usr/lib/hadoop/lib/native/libhadoop.so.1.0.0

In addition, that clazz object is only used for synchronization. In the case of the native method _deflateBytesDirect, the result is a class wide lock used to access the instance field uncompressed_direct_buf. Perhaps using the instance as the sync point is more appropriate?

Issue Links

• relates to: HADOOP-3604 Reduce stuck at shuffling phase