Re: PING: RFR: 8165736: Error message should be shown when JVMTI agent cannot be attached

Yasumasa Suenaga Tue, 21 Nov 2017 06:49:31 -0800

Hi Serguei,

On 2017/11/21 16:17, serguei.spit...@oracle.com wrote:

Hi Yasumasa,


Thank you for the update.

Some comments.

http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.04/src/jdk.attach/share/classes/sun/tools/attach/HotSpotVirtualMachine.java.frames.html

94 BufferedReader reader = new BufferedReader(new InputStreamReader(in));
95 try (reader) { A classic way for the above is: try (BufferedReader reader = 
new BufferedReader(new InputStreamReader(in))) {


I fixed it in new webrev:

  http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.05/

Also, I have a doubt about the change in HotSpotVirtualMachine.java:

      private void loadAgentLibrary(String agentLibrary, boolean isAbsolute, 
String options)
          throws AgentLoadException, AgentInitializationException, IOException
      {
+ String msgPrefix = "return code: ";
          InputStream in = execute("load",
                                   agentLibrary,
                                   isAbsolute ? "true" : "false",
                                   options);
- try {
- int result = readInt(in);
- if (result != 0) {
- throw new AgentInitializationException("Agent_OnAttach failed", result);
+ BufferedReader reader = new BufferedReader(new InputStreamReader(in));
+ try (reader) {
+ String result = reader.readLine();
+ if (result == null) {
+ throw new AgentLoadException("Target VM did not respond");
+ } else if (result.startsWith(msgPrefix)) {
+ int retCode = Integer.parseInt(result.substring(msgPrefix.length()));
+ if (retCode != 0) {
+ throw new AgentInitializationException("Agent_OnAttach failed", retCode);
+ }
+ } else {
+ throw new AgentLoadException(result);
              }
- } finally {
- in.close();
-
          }
      }


Now the AgentLoadException is thrown where it was not before. So that there is 
a change in behavior.
On the other hand the AgentLoadException was already specified to be thrown by 
the loadAgentLibrary.
I wonder, if this is worth to file a CSR for this.


IMHO this change need not to CSR because the spec is not changed. 
(AgentLoadException is already added to `throws`.)
I've not changed method signature in HotSpotVirtualMachine.java .


Thanks,

Yasumasa

Thanks,
Serguei


On 11/19/17 23:54, Yasumasa Suenaga wrote:

Hi David,

My own feeling is that it is up to the OnAttach function to properly deal with 
pending exceptions: report and/or clear them. The VM side just has to clear any 
pending exception to avoid it causing problems for later code.


I removed the change to print pending exceptions in new webrev:

http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.04/

test/jdk/com/sun/tools/attach/StartManagementAgent.java

The reporting of NumberFormatException may be accurate in terms of the low-level exception, but 
"Invalid com.sun.management.jmxremote.port number" was much clearer. This makes me wonder 
about whether the code that previously produced "Invalid com.sun.management.jmxremote.port 
number" needs updating if this change proceeds. (And alao makes me wonder about the impact of 
the change in general.)


I tested StartManagementAgent.java without this change, and I got failure as 
below:
--------------
JavaTest Message: Test threw exception: 
com.sun.tools.attach.AttachOperationFailedE
xception: java.lang.RuntimeException: 
jdk.internal.agent.AgentConfigurationError: j
ava.lang.NumberFormatException: For input string: "apa"
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: 
com.sun.tools.attach.AttachOperationFailedExc
eption: java.lang.RuntimeException: jdk.internal.agent.AgentConfigurationError: 
jav
a.lang.NumberFormatException: For input string: "apa"
--------------

Should we change this testcase whatever this change is not accepted?


Thanks,

Yasumasa


On 2017/11/20 6:41, David Holmes wrote:

Hi Yasumasa,

I've been trying to leave these reviews to serviceability folk ...

I've gone back through the original RFR from September last year to see what we 
did and what was left.

The current proposal raises some concern for me - and IIRC Dmitry was also 
concerned about it last time: printing of the pending exception. If we print 
the pending exception we will report an error and throw AgentLoadException, 
even if execution of the OnAttach function returned JNI_OK. If that exception 
was not critical to the success of the loading the agent, and the agent was 
just sloppy about clearing it, then it will now fail to load - which would be a 
compatibility concern.

Further, if the exception indicates an error and the OnAttach function returns JNI_ERR 
then we won't report that cleanly because the printing of the exception will prevent 
matching with "return code: -1".

My own feeling is that it is up to the OnAttach function to properly deal with 
pending exceptions: report and/or clear them. The VM side just has to clear any 
pending exception to avoid it causing problems for later code.

Some specific comments:

HotSpotVirtualMachine.java

The regex code seems overkill for the basic parsing you are doing. You just need to see 
if the strings starts with "return code: " and then parse the next bit as an 
integer to get the return code.

---

  test/jdk/com/sun/tools/attach/StartManagementAgent.java

The reporting of NumberFormatException may be accurate in terms of the low-level exception, but 
"Invalid com.sun.management.jmxremote.port number" was much clearer. This makes me wonder 
about whether the code that previously produced "Invalid com.sun.management.jmxremote.port 
number" needs updating if this change proceeds. (And alao makes me wonder about the impact of 
the change in general.)

---

Sorry - not the quick second review you were looking for.

David
-----

On 19/11/2017 11:38 PM, Yasumasa Suenaga wrote:

PING:

Could you review it?

http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.03/


I want to merge this change to jdk 10. So I need a second reviewer.


Yasumasa



On 2017/11/16 21:09, Yasumasa Suenaga wrote:

Hi David, Serguei,

The test logic is adding it in AttachFailedTestBase.java:

  45         return Paths.get(System.getProperty("test.nativepath"), "lib", 
libname)
  46                     .toAbsolutePath()
  47                     .toString();


Thanks!
I've fixed it in new webrev:

http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.03/


I've tested it as below. It works fine:

$ $JT_HOME/bin/jtreg -ignore:quiet -nativepath:$NATIVE_PATH 
hotspot/jtreg/serviceability/dcmd/jvmti/AttachFailed
$ echo $NATIVE_PATH
/<Path to configuration>/images/test/hotspot/jtreg/native


Thanks,

Yasumasa


On 2017/11/16 16:49, serguei.spit...@oracle.com wrote:

On 11/15/17 23:29, David Holmes wrote:

On 16/11/2017 4:43 PM, serguei.spit...@oracle.com wrote:

On 11/15/17 18:11, David Holmes wrote:

Hi Serguei,

> 
/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/test/hotspot/jtreg/native/lib/libException.so'

There should not be any "/lib/" in that path


Right, it should not be.


The test logic is adding it in AttachFailedTestBase.java:

  45         return Paths.get(System.getProperty("test.nativepath"), "lib", 
libname)
  46                     .toAbsolutePath()
  47                     .toString();

but it shouldn't.


Nice catch!
I looked right to these lines and overlooked it. :)

Thanks,
Serguei


David
-----

This is the script I'm using to run the tests:

#!/bin/sh

REPO=/var/tmp/sspitsyn/jdk.attach
IMAGES=${REPO}/build/linux-x86_64-normal-server-release/images
export JAVA_HOME=${IMAGES}/jdk
export NATIVE_PATH=${IMAGES}/../support/test/hotspot/jtreg/native
export NATIVE_PATH=${IMAGES}/test/hotspot/jtreg/native
echo "JAVA_HOME = $JAVA_HOME"

/java/re/jtreg/4.2/nightly/binaries/jtreg/bin/jtreg -nativepath:${NATIVE_PATH} \
$REPO/open/test/hotspot/jtreg/serviceability/dcmd/jvmti/AttachFailed


This is a part of log with the reported error from the AttachException.jtr:

[TestNG] Running:
serviceability/dcmd/jvmti/AttachFailed/AttachException.java

Running DCMD 'JVMTI.agent_load 
/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/test/hotspot/jtreg/native/lib/libException.so'
 through 'PidJcmdExecutor'
Executing command 
'[/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/jdk/bin/jcmd,
 8689, JVMTI.agent_load 
/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/test/hotspot/jtreg/native/lib/libException.so]'
Command returned with exit code 0
---------------- stdout ----------------
8689:
/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/test/hotspot/jtreg/native*/lib*/libException.so
 was not loaded.
/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/test/hotspot/jtreg/native*/lib*/libException.so:
 cannot open shared object file: No such file or directory


These are the locations of the libException.so:
build/linux-x86_64-normal-server-release/images/test/hotspot/jtreg/native/libException.so
build/linux-x86_64-normal-server-release/support/test/hotspot/jtreg/native/lib/libException.so


The tests fail with the "NATIVE_PATH=${IMAGES}/test/hotspot/jtreg/native"
but pass with the "export 
NATIVE_PATH=${IMAGES}/../support/test/hotspot/jtreg/native".


When the "export NATIVE_PATH=${IMAGES}/../support/test/hotspot/jtreg/native" is 
used
the log has this line:

Running DCMD 'JVMTI.agent_load 
/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/../support/test/hotspot/jtreg/native*/lib*/libException.so'
 through 'JMXExecutor'


Apparently, the sub-directory name "/lib" is added to the path.


Thanks,
Serguei

David

On 16/11/2017 4:34 AM, serguei.spit...@oracle.com wrote:

Hi Yasumasa and David,


On 11/15/17 04:56, David Holmes wrote:

On 15/11/2017 10:15 PM, Yasumasa Suenaga wrote:

Hi Serguei,

Do the new tests pass in your runs?


Of course.
It seems not to exist jtreg native libraries.
I've tested as below:

   $ make build-test-hotspot-jtreg-native
   $ cd test
   $ $JT_HOME/bin/jtreg -ignore:quiet 
-nativepath:<builddir>/<confdir>/support/test/hotspot/jtreg/native/lib 
hotspot/jtreg/serviceability/attach hotspot/jtreg/serviceability/dcmd/jvmti 
jdk/com/sun/tools/attach


Thanks.
I missed to add the -nativepath flag, sorry.

Please check that:

make test-image

followed by jtreg -nativepath:<build-dir>/images/test/hotspot/jtreg/native

also works.


It fails with the error:

   63 Running DCMD 'JVMTI.agent_load 
/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/test/hotspot/jtreg/native/lib/libException.so'
 through 'PidJcmdExecutor'
   64 Executing command 
'[/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/jdk/bin/jcmd,
 28407, JVMTI.agent_load 
/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/test/hotspot/jtreg
 /native/lib/libException.so]'
   65 Command returned with exit code 0
   66 ---------------- stdout ----------------
   67 28407:
   68 
/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/test/hotspot/jtreg/native/lib/libException.so
 was not loaded.
   69 
/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/test/hotspot/jtreg/native/lib/libException.so:
 cannot open shared object file: No such file or directory
   70


It seems, the '/lib' folder is added to the nativepath.

Yasumasa, could you, double check it please?

I'm using the jtreg:
/java/re/jtreg/4.2/promoted/latest/binaries/jtreg/bin/jtreg

which is:

% ls -l /java/re/jtreg/4.2/promoted/latest
lrwxrwxrwx 1 uucp 143 7 Nov  6 21:49 /java/re/jtreg/4.2/promoted/latest -> 
fcs/b10/


Thanks,
Serguei


Thanks,
David

Good news is that the attach-related tests from closed repository are passed.


Thanks!


Yasumasa


On 2017/11/15 16:38, serguei.spit...@oracle.com wrote:

Hi Yasumasa,

Do the new tests pass in your runs?

In my runs 3 of 4 tests are failed with the errors like this:

  109 Running DCMD 'JVMTI.agent_load 
/var/tmp/sspitsyn/tst/jdk.attach/JTwork/scratch/null/lib/libException.so' 
through 'PidJcmdExecutor'
  110 Executing command 
'[/var/tmp/sspitsyn/jdk.attach/build/linux-x86_64-normal-server-release/images/jdk/bin/jcmd,
 21951, JVMTI.agent_load 
/var/tmp/sspitsyn/tst/jdk.attach/JTwork/scratch/null/lib/libException.so]'
  111 Command returned with exit code 0
  112 ---------------- stdout ----------------
  113 21951:
  114 /var/tmp/sspitsyn/tst/jdk.attach/JTwork/scratch/null/lib/libException.so 
was not loaded.
  115 /var/tmp/sspitsyn/tst/jdk.attach/JTwork/scratch/null/lib/libException.so: 
cannot open shared object file: No such file or directory
  116


Good news is that the attach-related tests from closed repository are passed.


Thanks,
Serguei



On 11/14/17 16:40, serguei.spit...@oracle.com wrote:

Hi Yasumasa,

It looks good to me.

Thanks,
Serguei


On 11/7/17 22:38, Yasumasa Suenaga wrote:

Hi Serguei,

I uploaded new webrev:

http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.02/

I'd expect a check for some exception name, not for details like: For
input string: "apa".


Should we remove this comparison?


I don't understand. Why do remove?
Would it better to check for the exception name instead?

I've changed to check exception name (NumberFormatException) in
StartManagementAgent.java.

I will sponsor this fix and run these tests before the push.

Thanks!
I'm waiting for second reviewer.


Yasumasa


2017-11-08 11:55 GMT+09:00 serguei.spit...@oracle.com
<serguei.spit...@oracle.com>:

On 11/6/17 04:31, Yasumasa Suenaga wrote:

Hi Serguei,

On 2017/11/06 20:06, serguei.spit...@oracle.com wrote:

Hi Yasumasa,

The changes looks good.
Thank you for making them!


Thanks!

On 11/3/17 05:10, Yasumasa Suenaga wrote:

Hi Serguei,

Thank you for your comment!
I uploaded new webrev:

http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.01/

http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.00/test/jdk/com/sun/tools/attach/StartManagementAgent.java.udiff.html

- if (!ex.getMessage().contains("Invalid
com.sun.management.jmxremote.port number")) {
+ if (!ex.getMessage().contains("For input string: \"apa\"")) {


    What is the motivation for this change?
    It seems, the original comparison is better.


"ex" is AttachOperationFailedException.
We can get the result as below when we run StartManagementAgent:

-------------
[runApplication] Error: Invalid com.sun.management.jmxremote.port
number: apa
[runApplication] jdk.internal.agent.AgentConfigurationError:
java.lang.NumberFormatException: For input string: "apa"
[runApplication]        at
jdk.management.agent/sun.management.jmxremote.ConnectorBootstrap.startRemoteConnectorServer(ConnectorBootstrap.java:336)
-------------

I think we should check exception message in
AttachOperationFailedException.
In fact, jtreg fails at this point in my environment.



I'd expect a check for some exception name, not for details like: For
input string: "apa".


Should we remove this comparison?


I don't understand. Why do remove?
Would it better to check for the exception name instead?

What tests did you run to make sure there are no regressions?


I've tested the following testcases:

   - hotspot/jtreg/serviceability/attach
   - hotspot/jtreg/serviceability/dcmd/jvmti
   - jdk/com/sun/tools/attach


There are more tests related to dynamic attach in closed,
nsk.aod.testlist and 30+ attach tests in nsk.jvmti.testlist.
I'm not sure, if they are included into any of the Mach5 testing levels.
Will need to check.
We have to make sure these tests are still passed.


I cannot access JPRT and closed testcases because I'm not an Oracle
employee.
Can you run them with this change?


Ok.
I will sponsor this fix and run these tests before the push.

It seems, another update and one more review is needed.

Thanks,
Serguei


Thanks,

Yasumasa

Thanks,
Serguei

Thanks,

Yasumasa


On 2017/11/03 16:31, serguei.spit...@oracle.com wrote:

Hi Yasumasa,

Some comments.


http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.00/test/jdk/com/sun/tools/attach/StartManagementAgent.java.udiff.html

- if (!ex.getMessage().contains("Invalid
com.sun.management.jmxremote.port number")) {
+ if (!ex.getMessage().contains("For input string: \"apa\"")) {


    What is the motivation for this change?
    It seems, the original comparison is better.



http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.00/test/hotspot/jtreg/serviceability/dcmd/jvmti/AttachFailed/AttachException.java.html

http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.00/test/hotspot/jtreg/serviceability/dcmd/jvmti/AttachFailed/AttachIncorrectLibrary.java.html

http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.00/test/hotspot/jtreg/serviceability/dcmd/jvmti/AttachFailed/AttachNoEntry.java.html

http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.00/test/hotspot/jtreg/serviceability/dcmd/jvmti/AttachFailed/AttachReturnError.java.html

    37     public void run(CommandExecutor executor) {
    38         try{

    A space is missed after 'try'.


    It is odd that all test java classes define exactly the same
methods: sharedObjectName(), jmx() and cli().
    Would it better to defin a common base class with these methods?


Otherwise, it looks good.
Thank you for taking care about it!

What tests did you run to make sure there are no regressions?

Thanks,
Serguei



On 11/1/17 05:59, Yasumasa Suenaga wrote:

PING: Could you review and sponsor it?

http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.00/



Thanks,

Yasumasa


On 2017/09/29 13:24, Yasumasa Suenaga wrote:

Hi all,

If we try to attach invalid JVMTI agent via JVMTI.agent_load dcmd, we
will get "Command executed successfully". However, it implies error
in
JVMTIAgentLoadDCmd.
This message is from JCmd.java when jcmd does not receive any output
from target VM.

I think HotSopt/jcmd should return useful error message to users to
understand the cause of failure.

I uploaded webrev for this issue. Could you review it?

http://cr.openjdk.java.net/~ysuenaga/JDK-8165736/webrev.00/


This change is work fine on Fedora 26 x86_64 as following jtreg
testcases:

    - hotspot/jtreg/serviceability/attach
    - hotspot/jtreg/serviceability/dcmd/jvmti
    - jdk/com/sun/tools/attach

I cannot access JPRT. So I need a sponsor.
(I cannot test it on other platforms.)


Thanks,

Yasumasa

Re: PING: RFR: 8165736: Error message should be shown when JVMTI agent cannot be attached

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