[11u] RFR 8244287: JFR: Methods samples have line number 0

[Doerr, Martin]

Hi all,

we have seen several crashes on several platforms after this change was pushed.

Aarch64 example:
Stack: [0x0000ffff90437000,0x0000ffff90637000],  sp=0x0000ffff90635520,  free space=2041k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0x9fb0f8]  ObjectSampleCheckpoint::write_stacktrace(JfrStackTrace const*, JfrCheckpointWriter&)+0x208
V  [libjvm.so+0x9fb770]  StackTraceBlobInstaller::install(ObjectSample*)+0x1b8
V  [libjvm.so+0x9fba40]  ObjectSampleCheckpoint::on_rotation(ObjectSampler const*, JfrStackTraceRepository&)+0x150
V  [libjvm.so+0x72df6c]  JfrRecorderService::pre_safepoint_write()+0x3a4
V  [libjvm.so+0x72e828]  JfrRecorderService::write()+0x58
V  [libjvm.so+0x72fd2c]  JfrRecorderService::rotate(int)+0x3b4
V  [libjvm.so+0x730628]  recorderthread_entry(JavaThread*, Thread*)+0x160
V  [libjvm.so+0xbb2dd0]  JavaThread::thread_main_inner()+0xd8
V  [libjvm.so+0xbb08fc]  Thread::call_run()+0x94
V  [libjvm.so+0xa21718]  thread_native_entry(Thread*)+0x108
C  [libpthread.so.0+0x7088]  start_thread+0xb0

siginfo: si_signo: 11 (SIGSEGV), si_code: 1 (SEGV_MAPERR), si_addr: 0x0000000000000008


This backport uses a different JfrStackFrame constructor (which was probably unused before):
JfrStackFrame::JfrStackFrame(const traceid& id, int bci, int type, int lineno) :
  _method(NULL), _methodid(id), _line(lineno), _bci(bci), _type(type) {}

It sets _method to NULL!

Should probably be:
JfrStackFrame::JfrStackFrame(const traceid& id, int bci, int type, int lineno, const Method* method) :
  _method(method), _methodid(id), _line(lineno), _bci(bci), _type(type) {}

and:
_frames[count] = JfrStackFrame(mid, bci, type, lineno, method);

Do you think we can fix this quickly or should we better revert this backport?

Best regards,
Martin


> -----Original Message-----
> From: jdk-updates-dev <jdk-updates-dev-bounces at openjdk.java.net> On
> Behalf Of Lindenmaier, Goetz
> Sent: Montag, 22. Juni 2020 14:42
> To: Jaroslav Bachorík <jaroslav.bachorik at datadoghq.com>; jdk-updates-dev
> <jdk-updates-dev at openjdk.java.net>; hotspot-jfr-dev <hotspot-jfr-
> dev at openjdk.java.net>
> Subject: RE: [11u] RFR 8244287: JFR: Methods samples have line
> number 0
> 
> Hi Jaroslav,
> 
> The fix looks good to me.  Reviewed.
> Please flag the change with jdk11u-fix-request and
> add corresponding comment.
> 
> Best regards,
>   Goetz
> 
> 
> -----Original Message-----
> From: jdk-updates-dev <jdk-updates-dev-bounces at openjdk.java.net> On
> Behalf Of Jaroslav Bachorík
> Sent: Donnerstag, 18. Juni 2020 17:27
> To: jdk-updates-dev <jdk-updates-dev at openjdk.java.net>; hotspot-jfr-dev
> <hotspot-jfr-dev at openjdk.java.net>
> Subject: [11u] RFR 8244287: JFR: Methods samples have line number 0
> 
> Hi all,
> 
> Could I get this simple fix reviewed?
> It is fixing a regression introduced while backporting JDK-823790 and
> adding a new test to prevent such regressions in the future.
> 
> JIRA      :  https://bugs.openjdk.java.net/browse/JDK-8244287
> Webrev : http://cr.openjdk.java.net/~jbachorik/8244287/webrev/
> 
> Thanks,
> 
> -JB-