RFR : 8182672: Java 8u121 on Linux intermittently returns null for MAC address

[Vyom Tewari]

Hi Sean,

latest test code looks good, one minor bit, in MT program 
"ex.printStackTrace();" will not help as output will be screwed. I will 
suggested to pass the original exception to line 106.

throw new RuntimeException(originalException);

Thanks,

Vyom


On Friday 23 June 2017 03:26 PM, Seán Coffey wrote:
> Thanks to Christoph, Vyom and Mark for the reviews.
>
> I've improved the testcase as per feedback. Hope this meets all 
> requests :
>
> http://cr.openjdk.java.net/~coffeys/webrev.8182672.jdk10.v2/webrev/
>
> Regards,
> Sean.
>
> On 22/06/17 22:36, Langer, Christoph wrote:
>> Hi Sean,
>>
>> I played with it a bit more and now really understand Vyoms 
>> observation. So, what he sees is not the original concurrency issue 
>> but he encounters a SocketException on some interface, where this is 
>> supposed to occur upon calling getHardwareAddress().
>>
>> So, to enable the testcase to run robustly on any platform, any 
>> hardware and any network configuration, I suggest to modify the test 
>> like this:
>>
>> 1. In main, enumerate all interfaces once
>> 2. Iterate over all interfaces, exlude loopback and see if a single 
>> call to getHardwareAddress() won't yield null or an Exception.
>> 3. For each interface where a valid mac address could be obtained 
>> once, start the executor threads to stress getHardwareAddress() in 
>> parallel, e.g. like 5 threads doing it 100 times in parallel. I would 
>> also suggest to use per thread counters instead of one global 'count' 
>> as we have right now.
>>
>> Furthermore, the test output could be improved a bit, e.g. when it 
>> comes to an exception, the thread name could be mentioned, too.
>>
>> Best regards
>> Christoph
>>
>>> -----Original Message-----
>>> From: net-dev [mailto:net-dev-bounces at openjdk.java.net] On Behalf Of
>>> Seán Coffey
>>> Sent: Donnerstag, 22. Juni 2017 20:17
>>> To: Vyom Tewari <vyom.tewari at oracle.com>; net-dev <net-
>>> dev at openjdk.java.net>
>>> Subject: Re: RFR : 8182672: Java 8u121 on Linux intermittently 
>>> returns null for
>>> MAC address
>>>
>>> Hi Vyom,
>>>
>>> thanks for testing. Null is a valid value for some interfaces. I've
>>> excluded the loopback interface from being testing. Perhaps there's
>>> other issues at play here.  We know that getHardwareAddress() can throw
>>> SocketException if I/O fails. For this particular scenario we're not
>>> interested in that and perhaps that can be ignored.
>>>
>>> I'll take another look.
>>>
>>> regards,
>>> Sean.
>>>
>>> On 22/06/2017 18:50, Vyom Tewari wrote:
>>>> Hi Sean,
>>>>
>>>> with your patch as well your test case is failing on my
>>>> laptop(Ubuntu16.04), when i tried to run  on jdk8 i am getting below
>>>> error.
>>>>
>>>> java.net.SocketException: No such device (ioctl(SIOCGIFHWADDR) failed)
>>>>      at java.net.NetworkInterface.getMacAddr0(Native Method)
>>>>      at
>>>>
>>> java.net.NetworkInterface.getHardwareAddress(NetworkInterface.java:457
>>> )
>>>>      at com.java.test.GetMacAddress.run(GetMacAddress.java:66)
>>>>      at
>>>>
>>> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.jav 
>>>
>>> a:1142)
>>>>      at
>>>>
>>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.ja 
>>>
>>> va:617)
>>>>      at java.lang.Thread.run(Thread.java:745)
>>>> java.net.SocketException: No such device (ioctl(SIOCGIFHWADDR) failed)
>>>>      at java.net.NetworkInterface.getMacAddr0(Native Method)
>>>>      at
>>>>
>>> java.net.NetworkInterface.getHardwareAddress(NetworkInterface.java:457
>>> )
>>>>      at com.java.test.GetMacAddress.run(GetMacAddress.java:66)
>>>>      at
>>>>
>>> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.jav 
>>>
>>> a:1142)
>>>>      at
>>>>
>>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.ja 
>>>
>>> va:617)
>>>>      at java.lang.Thread.run(Thread.java:745)
>>>> Exception in thread "main" java.lang.RuntimeException: Failed
>>>>      at com.java.test.GetMacAddress.main(GetMacAddress.java:96)
>>>> mac id is null for interface cscotun0- Thread0
>>>> Testing: cscotun0
>>>> mac id is null for interface cscotun0- Thread3
>>>> Testing: cscotun0
>>>>
>>>> Thanks,
>>>>
>>>> Vyom
>>>>
>>>>
>>>> On Thursday 22 June 2017 09:59 PM, Seán Coffey wrote:
>>>>> JDK 10 fix required to correct a race issue in NetworkInterface. I
>>>>> don't believe the ifreq struct needs to be static in any case. New
>>>>> auto unit testcase also. I propose to skip this fix for JDK 9 and fix
>>>>> in an update release for that family. I also plan to port this to
>>>>> jdk8u-dev.
>>>>>
>>>>> https://bugs.openjdk.java.net/browse/JDK-8182672
>>>>> webrev :
>>>>> http://cr.openjdk.java.net/~coffeys/webrev.8182672.jdk10/webrev/
>>>>>
>>>>> regards,
>>>>> Sean.
>