Hi David,
On 2/20/18 20:02, David Holmes wrote:
Hi Daniil,
Good find on this!
What does the actual spec say about the length of things and how they
may be split across multiple packets? Are we guaranteed that at most
two packets will be involved? What about for other things eg:
68 protected byte[] readJdwpString(DataInputStream ds) throws
IOException {
69 byte[] str = null;
70 int len = ds.readInt();
71 if (len > 0) {
72 str = new byte[len];
73 ds.read(str, 0, len);
74 }
might we get a short-read of the string if it is split across multiple
packets?
Nice catch!
Even though this fix is enough to resolve this problem now, there is a
chance,
it can fail in the future when more modules are added to the platform.
I'm wondering if all these reads should be loops, ensuring we read the
expected amount of data.
One further comment - not sure why we need the print out for when we
do read multiple packets?
That would seem to be a debugging aid.
Yes, it helps to understand what happens.
Many tests have a lack of tracing which makes it harder to debug and
understand failures.
Thanks,
Serguei
Thanks,
David
On 21/02/2018 10:14 AM, Daniil Titov wrote:
Hi Serguei,
A new version of the webrev that has these strings reformatted is at
http://cr.openjdk.java.net/~dtitov/8170541/webrev.02/
Thank you!
Best regards,
Daniil
*From: *"serguei.spit...@oracle.com" <serguei.spit...@oracle.com>
*Date: *Tuesday, February 20, 2018 at 3:00 PM
*To: *Daniil Titov <daniil.x.ti...@oracle.com>,
"serviceability-dev@openjdk.java.net"
<serviceability-dev@openjdk.java.net>
*Subject: *Re: RFR 8170541:
serviceability/jdwp/AllModulesCommandTest.java fails intermittently
on Windows and Solaris
Hi Daniil,
Interesting issue...
Thank you for finding to the root cause so quickly!
The fix looks good.
Could I ask you to reformat these lines to make the L54 shorter ?:
54 System.out.println("[" + getClass().getName() +
"] Only " + bytesRead + " bytes of " + dataLength +
55 " were read in the first packet.
Reading the rest...");
Thanks,
Serguei
On 2/20/18 09:24, Daniil Titov wrote:
Please review the changes that fix intermittent failure of
serviceability/jdwp/AllModulesCommandTest.java test.
The problem here is that for a large data the JDWP agent
(socketTransport_writePacket() method in
src/jdk.jdwp.agent/share/native/libdt_socket/socketTransport.c )
sends 2 packets and in some cases only the first packet is received
at the time when the test reads the reply from the JDWP agent. Since
the test does not check that all data is received in the first
packet the correlation between commands and replies became broken
(the unread second packet is read by the next command and the reply
for the next command is read by the next after next command and
so on).
Bug: https://bugs.openjdk.java.net/browse/JDK-8170541
Webrev: http://cr.openjdk.java.net/~dtitov/8170541/webrev.01
The tests ran successfully with Mach5.
Best regards,
Daniil
