Buffer overflow in jcmd GC.class_stats due to too many classes

Test failed with
#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (open/src/hotspot/share/utilities/ostream.cpp:997), pid=6734, tid=6766
# assert(false) failed: Exceeded max buffer size for this string.
#
# JRE version: Java(TM) SE Runtime Environment (14.0+24) (fastdebug build 14-ea+24-1068)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 14-ea+24-1068, mixed mode, tiered, z gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x13b959c] bufferedStream::write(char const*, unsigned long)+0x17c
#
# Core dump will be written. Default location: Core dumps may be processed with "/opt/core.sh %p" (or dumping to /opt/mach5/mesos/work_dir/slaves/fcf4c0c4-d73e-4321-860c-6613427db92b-S2190/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/6107b495-02d7-4611-83e5-02a265731c06/runs/432907b4-7e05-48ef-991c-54020f3ff8b0/testoutput/test-support/jtreg_closed_test_hotspot_jtreg_applications_runthese_RunThese24H_java/scratch/0/core.6734)
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp
#

--------------- S U M M A R Y ------------

Command Line: -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:MaxRAMPercentage=6 -XX:+UnlockExperimentalVMOptions -XX:+UseZGC -XX:MaxRAMPercentage=50 -Djava.net.preferIPv6Addresses=false -XX:+DisplayVMOutputToStderr -Xlog:gc*,gc+heap=debug:gc.log:uptime,timemillis,level,tags -XX:+DisableExplicitGC -XX:+StartAttachListener --add-exports=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED --add-exports=java.xml/com.sun.org.apache.xerces.internal.parsers=ALL-UNNAMED --add-exports=java.xml/com.sun.org.apache.xerces.internal.util=ALL-UNNAMED -Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/fcf4c0c4-d73e-4321-860c-6613427db92b-S2190/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/6107b495-02d7-4611-83e5-02a265731c06/runs/432907b4-7e05-48ef-991c-54020f3ff8b0/testoutput/test-support/jtreg_closed_test_hotspot_jtreg_applications_runthese_RunThese24H_java/scratch/0/java.io.tmpdir -Duser.home=/opt/mach5/mesos/work_dir/slaves/fcf4c0c4-d73e-4321-860c-6613427db92b-S2190/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/6107b495-02d7-4611-83e5-02a265731c06/runs/432907b4-7e05-48ef-991c-54020f3ff8b0/testoutput/test-support/jtreg_closed_test_hotspot_jtreg_applications_runthese_RunThese24H_java/scratch/0/user.home -agentpath:/opt/mach5/mesos/work_dir/jib-master/install/jdk-14+24-1068/linux-x64-debug.test/hotspot/jtreg/native/libJvmtiStressModule.so -XX:NativeMemoryTracking=detail applications.kitchensink.process.stress.Main /opt/mach5/mesos/work_dir/slaves/fcf4c0c4-d73e-4321-860c-6613427db92b-S2190/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/6107b495-02d7-4611-83e5-02a265731c06/runs/432907b4-7e05-48ef-991c-54020f3ff8b0/testoutput/test-support/jtreg_closed_test_hotspot_jtreg_applications_runthese_RunThese24H_java/scratch/0/kitchensink.final.properties

Host: Intel(R) Xeon(R) Platinum 8167M CPU @ 2.00GHz, 8 cores, 58G, Oracle Linux Server release 7.6
Time: Sat Nov 16 14:58:16 2019 UTC elapsed time: 53459 seconds (0d 14h 50m 59s)

--------------- T H R E A D ---------------

Current thread (0x00007fc0fc2d60b0): VMThread "VM Thread" [stack: 0x00007fbecdf00000,0x00007fbece000000] [id=6766]

Stack: [0x00007fbecdf00000,0x00007fbece000000], sp=0x00007fbecdffd950, free space=1014k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x13b959c] bufferedStream::write(char const*, unsigned long)+0x17c
V [libjvm.so+0x13b9a88] outputStream::do_vsnprintf_and_write_with_automatic_buffer(char const*, __va_list_tag*, bool)+0xf8
V [libjvm.so+0x13b9da9] outputStream::print(char const*, ...)+0xd9
V [libjvm.so+0xcce622] KlassInfoHisto::print_class_stats(outputStream*, bool, char const*)+0x6d2
V [libjvm.so+0xccf823] HeapInspection::heap_inspection(outputStream*)+0x743
V [libjvm.so+0xc65866] VM_GC_HeapInspection::doit()+0x86
V [libjvm.so+0x172c603] VM_Operation::evaluate()+0x143
V [libjvm.so+0x175b138] VMThread::evaluate_operation(VM_Operation*) [clone .constprop.66]+0x2b8
V [libjvm.so+0x175bb1f] VMThread::loop()+0x82f
V [libjvm.so+0x175beaa] VMThread::run()+0xca
V [libjvm.so+0x1675656] Thread::call_run()+0xf6
V [libjvm.so+0x13a783e] thread_native_entry(Thread*)+0x10e

Register to memory mapping:

RAX=0x00007fc104897000 points into unknown readable memory: 58 00 00 00 00 00 00 00
RBX=0x00007fbecdbc1d90 is pointing into the stack for thread: 0x00007fc0fc377310
RCX=0x00007fc103766100: <offset 0x0000000001933100> in /opt/mach5/mesos/work_dir/jib-master/install/jdk-14+24-1068/linux-x64-debug.jdk/jdk-14/fastdebug/lib/server/libjvm.so at 0x00007fc101e33000
RDX=0x00007fc1037b39e1: <offset 0x00000000019809e1> in /opt/mach5/mesos/work_dir/jib-master/install/jdk-14+24-1068/linux-x64-debug.jdk/jdk-14/fastdebug/lib/server/libjvm.so at 0x00007fc101e33000
RSP=0x00007fbecdffd950 points into unknown readable memory: 90 1d bc cd be 7f 00 00
RBP=0x00007fbecdffd980 points into unknown readable memory: b0 e1 ff cd be 7f 00 00
RSI=0x00000000000003e5 is an unknown value
RDI=0x00007fc103765f98: <offset 0x0000000001932f98> in /opt/mach5/mesos/work_dir/jib-master/install/jdk-14+24-1068/linux-x64-debug.jdk/jdk-14/fastdebug/lib/server/libjvm.so at 0x00007fc101e33000
R8 =0x00000000000007d0 is an unknown value
R9 =0x000000000000005f is an unknown value
R10=0x2e3130306b636568 is an unknown value
R11=0x00007fc103e02650: <offset 0x000000000018e650> in /lib64/libc.so.6 at 0x00007fc103c74000
R12=0x00007fbecdffd9a0 points into unknown readable memory: 20 6a 61 76 61 73 6f 66
R13=0x000000000000005f is an unknown value
R14=0x0000000006400000 is an unknown value
R15=0x0000000008000000 is an unknown value


Registers:
RAX=0x00007fc104897000, RBX=0x00007fbecdbc1d90, RCX=0x00007fc103766100, RDX=0x00007fc1037b39e1
RSP=0x00007fbecdffd950, RBP=0x00007fbecdffd980, RSI=0x00000000000003e5, RDI=0x00007fc103765f98
R8 =0x00000000000007d0, R9 =0x000000000000005f, R10=0x2e3130306b636568, R11=0x00007fc103e02650
R12=0x00007fbecdffd9a0, R13=0x000000000000005f, R14=0x0000000006400000, R15=0x0000000008000000
RIP=0x00007fc1031ec59c, EFLAGS=0x0000000000010287, CSGSFS=0x002b000000000033, ERR=0x0000000000000006
  TRAPNO=0x000000000000000e

Top of Stack: (sp=0x00007fbecdffd950)
0x00007fbecdffd950: 00007fbecdbc1d90 00007fbecdffd9a0
0x00007fbecdffd960: 0000000000000000 00007fbecdbc1d90
0x00007fbecdffd970: 00000000000007cf 00007fbecdffd9a0
0x00007fbecdffd980: 00007fbecdffe1b0 00007fc1031eca88

Instructions: (pc=0x00007fc1031ec59c)
0x00007fc1031ec49c: 00 00 00 49 39 d7 76 1c 48 8b 7b 48 31 c9 ba 08
0x00007fc1031ec4ac: 00 00 00 4c 89 fe e8 49 15 21 ff 4c 89 7b 60 48
0x00007fc1031ec4bc: 89 43 48 90 4d 85 ed 75 13 48 83 c4 08 5b 41 5c
0x00007fc1031ec4cc: 41 5d 41 5e 41 5f 5d c3 0f 1f 40 00 48 8b 7b 50
0x00007fc1031ec4dc: 4c 89 ea 4c 89 e6 48 03 7b 48 e8 45 43 f3 fe 4c
0x00007fc1031ec4ec: 01 6b 50 8b 43 20 4c 89 e6 4d 01 e5 b9 08 00 00
0x00007fc1031ec4fc: 00 eb 15 90 80 fa 09 74 33 83 c0 01 89 43 20 48
0x00007fc1031ec50c: 83 c6 01 4c 39 ee 74 b1 0f b6 16 80 fa 0a 75 e4
0x00007fc1031ec51c: 83 c0 01 83 43 24 01 48 98 c7 43 20 00 00 00 00
0x00007fc1031ec52c: 48 01 43 28 31 c0 eb d7 0f 1f 40 00 89 c2 f7 d0
0x00007fc1031ec53c: 83 e2 f8 83 e0 07 48 29 43 28 01 ca 89 53 20 89
0x00007fc1031ec54c: d0 eb bc 90 c3 0f 1f 80 00 00 00 00 4c 8d 6a ff
0x00007fc1031ec55c: c6 43 69 01 49 29 cd 4d 85 ed 0f 84 59 ff ff ff
0x00007fc1031ec56c: e9 67 ff ff ff 0f 1f 80 00 00 00 00 48 8d 05 b9
0x00007fc1031ec57c: 3d 98 00 48 8d 0d 7a 9b 57 00 48 8d 15 54 74 5c
0x00007fc1031ec58c: 00 be e5 03 00 00 48 8d 3d ff 99 57 00 48 8b 00
0x00007fc1031ec59c: c6 00 58 31 c0 e8 9a ad 63 ff e8 75 5d fe ff 4c
0x00007fc1031ec5ac: 89 f0 48 2b 43 50 49 39 c5 72 08 c6 43 69 01 4c
0x00007fc1031ec5bc: 8d 68 ff 48 8b 53 60 4d 89 f7 e9 d4 fe ff ff 90
0x00007fc1031ec5cc: 0f 1f 40 00 55 48 89 e5 41 54 41 89 f4 53 48 89
0x00007fc1031ec5dc: fb e8 6e 23 21 ff 48 8d 05 17 e0 95 00 44 89 63
0x00007fc1031ec5ec: 1c 48 89 03 c7 43 18 00 00 00 00 48 c7 43 20 00
0x00007fc1031ec5fc: 00 00 00 48 c7 43 28 00 00 00 00 48 c7 43 30 00
0x00007fc1031ec60c: 00 00 00 48 c7 43 38 00 00 00 00 48 c7 43 40 00
0x00007fc1031ec61c: 00 00 00 5b 41 5c 5d c3 66 66 2e 0f 1f 84 00 00
0x00007fc1031ec62c: 00 00 00 90 55 48 89 e5 41 55 41 89 f5 41 54 41
0x00007fc1031ec63c: 89 d4 53 48 89 fb 48 83 ec 08 e8 05 23 21 ff 48
0x00007fc1031ec64c: 8d 05 ae df 95 00 44 89 6b 1c 48 89 03 c7 43 18
0x00007fc1031ec65c: 00 00 00 00 48 c7 43 20 00 00 00 00 48 c7 43 28
0x00007fc1031ec66c: 00 00 00 00 48 c7 43 30 00 00 00 00 48 c7 43 38
0x00007fc1031ec67c: 00 00 00 00 48 c7 43 40 00 00 00 00 45 84 e4 75
0x00007fc1031ec68c: 13 48 83 c4 08 5b 41 5c 41 5d 5d c3 0f 1f 84 00


Stack slot to memory mapping:
stack at sp + 0 slots: 0x00007fbecdbc1d90 is pointing into the stack for thread: 0x00007fc0fc377310
stack at sp + 1 slots: 0x00007fbecdffd9a0 points into unknown readable memory: 20 6a 61 76 61 73 6f 66
stack at sp + 2 slots: 0x0 is NULL
stack at sp + 3 slots: 0x00007fbecdbc1d90 is pointing into the stack for thread: 0x00007fc0fc377310
stack at sp + 4 slots: 0x00000000000007cf is an unknown value
stack at sp + 5 slots: 0x00007fbecdffd9a0 points into unknown readable memory: 20 6a 61 76 61 73 6f 66
stack at sp + 6 slots: 0x00007fbecdffe1b0 points into unknown readable memory: a0 e2 ff cd be 7f 00 00
stack at sp + 7 slots: 0x00007fc1031eca88: <offset 0x00000000013b9a88> in /opt/mach5/mesos/work_dir/jib-master/install/jdk-14+24-1068/linux-x64-debug.jdk/jdk-14/fastdebug/lib/server/libjvm.so at 0x00007fc101e33000

VM_Operation (0x00007fbecdbc1ba0): GC_HeapInspection, mode: safepoint, requested by thread 0x00007fc0fc377310