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-boun...@openjdk.java.net] On Behalf Of > Seán Coffey > Sent: Donnerstag, 22. Juni 2017 20:17 > To: Vyom Tewari <vyom.tew...@oracle.com>; net-dev <net- > d...@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. > >
