Georg Hajdu

I have reported this problem a couple of months ago to the general 

Max list but have never received an answer.

My problem concerns mxj net.tcp.send, and is as follows:

1. I have computer A sitting behind a NAT router connecting to 

computer B on the Internet via net.tcp.send.

2. On computer B I have a Max patch running with an instance of mxj 

3. This instance now receives instructions from computer A to open 

another patch and to send some messages to the originating computer 

(i.e. A), after setting an instance of mxj net.tcp.send to computer 

1. the address computer B receives computer A's local IP address 

(instead of its public address) and tries to send messages to this IP 

2. upon noticing the error, computer B terminates the connection and 

closes the Max patch with the mxj net.tcp.send instance with 30 

3. Max crashes after approx. 90 seconds with the following crash log:

0 libjvm.dylib     0x9a757c74 JVM_GetLastErrorString 

1 libjvm.dylib     0x9a63e998 JNI_CreateJavaVM_Impl 

2 libjvm.dylib     0x9a63e88c JNI_CreateJavaVM_Impl 

3 libSystem.B.dylib     0x9002ba68 _pthread_body + 96

It seems to me that the problem exists due to a miscommunication 

I have reported this problem a couple of months ago to the general  
Max list but have never received an answer.
My problem concerns mxj net.tcp.send, and is as follows:

1. I have computer A sitting behind a NAT router connecting to  
computer B on the Internet via net.tcp.send.
2. On computer B I have a Max patch running with an instance of mxj  
net.tcp.recv.
3. This instance now receives instructions from computer A to open  
another patch and to send some messages to the originating computer  
(i.e. A), after setting an instance of mxj net.tcp.send to computer  
A's IP address.

The problem arises when
1. the address computer B receives computer A's local IP address  
(instead of its public address) and tries to send messages to this IP  
address.
2. upon noticing the error, computer B terminates the connection and  
closes the Max patch with the mxj net.tcp.send instance with 30  
active packets waiting to be delivered.
3. Max crashes after approx. 90 seconds with the following crash log:

Thread 4 Crashed:
0   libjvm.dylib                   	0x9a757c74 JVM_GetLastErrorString  
+ 8420
1   libjvm.dylib                   	0x9a63e998 JNI_CreateJavaVM_Impl  
+ 44252
2   libjvm.dylib                   	0x9a63e88c JNI_CreateJavaVM_Impl  
+ 43984
3   libSystem.B.dylib              	0x9002ba68 _pthread_body + 96

It seems to me that the problem exists due to a miscommunication  
between Max and JVM.

net-tcp-connection-problems-leading-to-consistent-crashes

> I have reported this problem a couple of months ago to the general

> Max list but have never received an answer.

The answer I gave you then was that I can't reproduce this crash. I

just tried to emulate the situation you describe and I still can't

reproduce the crash. Until you can create an example patch that

reproducibly crashes we will probably not make much progress.

> I have reported this problem a couple of months ago to the general
> Max list but have never received an answer.

The answer I gave you then was that I can't reproduce this crash.  I
just tried to emulate the situation you describe and I still can't
reproduce the crash.  Until you can create an example patch that
reproducibly crashes we will probably not make much progress.

Would it help if I gave you VNC access to our server? Because, 

otherwise, you may never be able to witness the crash, as it involves 

a remote XServe server running Max/MSP. Have you ever used Chicken of 

the VNC? If you're fine with my suggestion I'll send you the access 

Would it help if I gave you VNC access to our server? Because,  
otherwise, you may never be able to witness the crash, as it involves  
a remote XServe server running Max/MSP. Have you ever used Chicken of  
the VNC? If you're fine with my suggestion I'll send you the access  
data offline.

I painstakingly created after much trial and error a patch which will 

most likely demonstrate the crash on your machine with no need for an 

external server. It crashes my machine (Powerbook G4 1.25 GHz, Mac OS 

X 10.4.6, Max 4.5.7, Java 1.4.2) and a XServe (G4 1.0 GHz, Mac OS X 

Server 10.4.6, Max 4.5.7, Java 1.5). Please move the enclosed folder 

into the patches folder after moving the Java classes to the net->tcp 

I'm realizing that the crash may even have something to do with the 

printing of an error message to the Max window, but I'll leave this 

to you to figure this out, as this is only an educated guess.

On Jun 18, 2006, at 6:58 PM, Ben Nevile wrote:

>> I have reported this problem a couple of months ago to the general

>> Max list but have never received an answer.

> The answer I gave you then was that I can't reproduce this crash. I

> just tried to emulate the situation you describe and I still can't

> reproduce the crash. Until you can create an example patch that

> reproducibly crashes we will probably not make much progress.

>> My problem concerns mxj net.tcp.send, and is as follows:

>> 1. I have computer A sitting behind a NAT router connecting to

>> computer B on the Internet via net.tcp.send.

>> 2. On computer B I have a Max patch running with an instance of mxj

>> 3. This instance now receives instructions from computer A to open

>> another patch and to send some messages to the originating computer

>> (i.e. A), after setting an instance of mxj net.tcp.send to computer

>> 1. the address computer B receives computer A's local IP address

>> (instead of its public address) and tries to send messages to this IP

>> 2. upon noticing the error, computer B terminates the connection and

>> closes the Max patch with the mxj net.tcp.send instance with 30

>> active packets waiting to be delivered.

>> 3. Max crashes after approx. 90 seconds with the following crash log:

>> 3 libSystem.B.dylib 0x9002ba68 _pthread_body + 96

>> It seems to me that the problem exists due to a miscommunication

I painstakingly created after much trial and error a patch which will  
most likely demonstrate the crash on your machine with no need for an  
external server. It crashes my machine (Powerbook G4 1.25 GHz, Mac OS  
X 10.4.6, Max 4.5.7, Java 1.4.2) and a XServe (G4 1.0 GHz, Mac OS X  
Server 10.4.6, Max 4.5.7, Java 1.5). Please move the enclosed folder  
into the patches folder after moving the Java classes to the net->tcp  
folder.

I'm realizing that the crash may even have something to do with the  
printing of an error message to the Max window, but I'll leave this  
to you to figure this out, as this is only an educated guess.

>> I have reported this problem a couple of months ago to the general
>> Max list but have never received an answer.
>
> The answer I gave you then was that I can't reproduce this crash.  I
> just tried to emulate the situation you describe and I still can't
> reproduce the crash.  Until you can create an example patch that
> reproducibly crashes we will probably not make much progress.
>
> Ben
>
>
>
>
>> My problem concerns mxj net.tcp.send, and is as follows:
>>
>> 1. I have computer A sitting behind a NAT router connecting to
>> computer B on the Internet via net.tcp.send.
>> 2. On computer B I have a Max patch running with an instance of mxj
>> net.tcp.recv.
>> 3. This instance now receives instructions from computer A to open
>> another patch and to send some messages to the originating computer
>> (i.e. A), after setting an instance of mxj net.tcp.send to computer
>> A's IP address.
>>
>> The problem arises when
>> 1. the address computer B receives computer A's local IP address
>> (instead of its public address) and tries to send messages to this IP
>> address.
>> 2. upon noticing the error, computer B terminates the connection and
>> closes the Max patch with the mxj net.tcp.send instance with 30
>> active packets waiting to be delivered.
>> 3. Max crashes after approx. 90 seconds with the following crash log:
>>
>> Thread 4 Crashed:
>> 0   libjvm.dylib                        0x9a757c74  
>> JVM_GetLastErrorString
>> + 8420
>> 1   libjvm.dylib                        0x9a63e998  
>> JNI_CreateJavaVM_Impl
>> + 44252
>> 2   libjvm.dylib                        0x9a63e88c  
>> JNI_CreateJavaVM_Impl
>> + 43984
>> 3   libSystem.B.dylib                   0x9002ba68 _pthread_body + 96
>>
>> It seems to me that the problem exists due to a miscommunication
>> between Max and JVM.
>>
>> Georg
>>
>>

I wonder if it is related to a crash I found when trying to openConnection() or openStream() to a URL. If I would post, I would crash, however System.out.println would work fine. Perhaps try that? Total shot in the dark.

I simply extended the existing net.tcp.send and receive objects by 

some simple list processing stuff. The problem probably lies in the 

sheer size of the packets not being able to be delivered when the IP 

address doesn't exist. After time-out net.tcp.packer (as I call my 

pbject) prints an error message to the Max window and I'm wondering 

whether that's where the problems lies. Unfortunately, I can't modify 

> I wonder if it is related to a crash I found when trying to 

> openConnection() or openStream() to a URL. If I would post, I would 

> crash, however System.out.println would work fine. Perhaps try 

I simply extended the existing net.tcp.send and receive objects by  
some simple list processing stuff. The problem probably lies in the  
sheer size of the packets not being able to be delivered when the IP  
address doesn't exist. After time-out net.tcp.packer (as I call my  
pbject) prints an error message to the Max window and I'm wondering  
whether that's where the problems lies. Unfortunately, I can't modify  
the TcpSender class.

>
> I wonder if it is related to a crash I found when trying to  
> openConnection() or openStream() to a URL. If I would post, I would  
> crash, however System.out.println would work fine. Perhaps try  
> that? Total shot in the dark.
>
> Ah.. Max and idiosyncrasies.


net.tcp.* connection problems leading to consistent crashes