On 26/06/2018 11:32 AM, Daniel D. Daugherty wrote:
David,
Thanks for your eagle eyes! More below...
On 6/25/18 9:27 AM, Daniel D. Daugherty wrote:
On 6/25/18 1:57 AM, David Holmes wrote:
Hi Dan,
On 21/06/2018 10:18 AM, Daniel D. Daugherty wrote:
Greetings,
I have a fix for a recent (very rare) Thread-SMR related test failure.
Since the fix is related to the ErrorHandling tests and affects
hs_err_pid
file generation, this code review is being sent to both the Runtime and
the Serviceability teams. Please make sure you reply-all to any
responses
so we have complete review threads on both aliases.
Bug URL: https://bugs.openjdk.java.net/browse/JDK-8205195
Webrev URL:
http://cr.openjdk.java.net/~dcubed/8205195-webrev/0-for-jdk-jdk/
The bug itself contains analysis about the root cause of the bug and
the comment updates to the code describes the no win scenario that the
hs_err_pid file generation code is in. Of course, I also have a comment
where I was able to harden the ErrorHandling tests. I did manage to
resist the urge to mention the "Kobiyashi Maru" [1] in the new
comments.
Testing: Mach5
builds-tier1,jdk-tier1,jdk-tier2,hs-tier1,hs-tier2,hs-tier3
on the usual Oracle platforms.
Thanks, in advance, for any comments, questions or suggestions.
I don't quite follow the fix.
I think this comment explains what the fix is _trying_ to do:
1702 // We grab Threads_lock to keep ThreadsSMRSupport::print_info_on()
1703 // from racing with Threads::add() or Threads::remove() as we
1704 // generate the hs_err_pid file. This makes our ErrorHandling
tests
1705 // more stable.
Won't you self-deadlock on acquiring the Threads_lock in the
secondary error handler test, due to the recursive call to
controlled_crash ?
I missed that possibility, but now I'm puzzled why my testing didn't
reveal this situation. We have a test for secondary error handling
and it should have self-deadlocked (and failed). I'll investigate.
The ErrorHandling tests don't run with 'release' bits so no self-deadlock.
The 'fastdebug' and 'slowdebug' versions will fail an assertion that gets
hidden by the fact that it is a secondary failure mode.
Ah - of course.
I've filed the following bug:
JDK-8205648 fix for 8205195 breaks secondary error handling
https://bugs.openjdk.java.net/browse/JDK-8205648
Thanks,
David
Dan
Dan
David
Dan
[1] https://www.urbandictionary.com/define.php?term=Kobayashi%20Maru
