Hi Yasumasa,
On 7/11/19 05:10, Yasumasa Suenaga wrote:
Hi Serguei,
On 2019/07/11 17:06, serguei.spit...@oracle.com wrote:
Hi Yasumasa,
On 7/10/19 23:56, Yasumasa Suenaga wrote:
Hi Serguei,
2019年7月11日(木) 15:23 serguei.spit...@oracle.com
<mailto:serguei.spit...@oracle.com> <serguei.spit...@oracle.com
<mailto:serguei.spit...@oracle.com>>:
Hi Yasumasaa,
It looks good to me in general.
It is hard to prove the Attach Listener initialization state
machine is fully correct.
One comment though.
+bool AttachListener::check_socket_file() {
. . .
+ is_init_trigger();
+ return true;
+ }
+ return false;
+} I was expecting a value fromthe is_init_trigger() call be
returned:
returnis_init_trigger(); Do I miss anything here?
I expect check_socket_file() returns whether is_init_trigger() was
kicked. So I return true at this point.
Should this function return the result of is_init_trigger()?
It is not clear to me what is your intention.
Is it Okay for the check_socket_file() to return true even if the
is_init_trigger() returned false?
I'm not particular about this.
So I uploaded new webrev which redirects the result of is_init_trigger().
http://cr.openjdk.java.net/~ysuenaga/JDK-8225690/webrev.02/
The change from previous webrev:
http://hg.openjdk.java.net/jdk/submit/rev/7740b1b1f2f6
The update looks Okay to me.
Thanks,
Serguei
Thanks,
Yasumasa
Thanks,
Serguei
Thanks,
Yasumasa
Thanks, Serguei
On 7/10/19 17:18, Yasumasa Suenaga wrote:
Hi Chris,
Thank you for your comment!
I uploaded new webrev:
http://cr.openjdk.java.net/~ysuenaga/JDK-8225690/webrev.01/
I write some comments the following.
On 2019/07/11 4:29, Chris Plummer wrote:
Hi Yasumasa,
I just took a quick look at this. I understand a little about
how the attach mechanism works, but am by no means an expert, and
find myself easily lost in some of the logic. I'll look again
after others have also contributed comments. Here area few comments.
I don't understand the need for the following in
attach_listener_thread_entry()
428 AttachListener::set_state(AL_NOT_INITIALIZED);
There is no path to this statement since the only way out of
the loop is the following:
I agree with you, but I think we need to reset the status of
Attach Listener
in the end of the function.
We might be able to use ShouldNotReachHere() at here.
How are errors in AttachListener::init() properly propagated.
I see is_init_trigger() does the following:
548 if
(os::Posix::matches_effective_uid_or_root(st.st_uid)) {
549 init();
550 log_trace(attach)("Attach triggered by %s", fn);
551 return true;
So "true" is returned even though init() maybe have failed,
but then check_socket_file() doesn't even check the result from
is_init_trigger():
509 is_init_trigger();
510 return true;
The SIGBREAK code does check the is_init_trigger() result, but
since init() failures are not propagated to is_init_trigger(), the
result may not be accurate.
In case of Linux, HotSpot has some phase to start Attach Listener:
1. Check attach file (.attach_pid*) -> is_init_trigger()
2. Create unix domain socket -> is_init_trigger()
3. Start Attach Listener thread -> init()
is_init_trigger() returns whether init() is kicked or not.
OTOH init() is declared as a void function, so we cannot know
Attach Listener is started.
(We can know it through exception message on the console, but
it will not handle in HotSpot.)
Thus I thought we can add new field AttachListener::_state
to know current status of Attach Listener.
Have you done any testing of the error handling by forcing
errors to happen?
Do you mean it is the race of the attach request?
If so, I've added the testcase (ConcAttachTest.java).
If you mean the failure of init() and/or is_init_trigger(),
I do not have idea how to test it.
The following code needs a comment to indicate that the
current state is AL_INITIALIZED, and if the socket file was
removed it needs to be recreated and a new socket opened.
379 } else if (AttachListener::check_socket_file()) {
380 continue;
381 }
I added it in new webrev.
Thanks,
Yasumasa
thanks,
Chris
On 7/4/19 6:27 AM, Yasumasa Suenaga wrote:
Hi all,
Please review this change:
JBS: https://bugs.openjdk.java.net/browse/JDK-8225690
webrev:
http://cr.openjdk.java.net/~ysuenaga/JDK-8225690/webrev.00/
This issue has been discussed on [1] and [2].
This webrev passed tests on submit repo
(mach5-one-ysuenaga-JDK-8225690-20190704-1214-3626907).
It includes the fix for JDK-8225193. They relate each other,
so I fix them together.
Thanks,
Yasumasa
[1]
https://mail.openjdk.java.net/pipermail/serviceability-dev/2019-July/028585.html
[2]
https://mail.openjdk.java.net/pipermail/serviceability-dev/2019-June/028418.html
