[8u] RFR: JDK-8220786: Create new switch to redirect error reporting output to stdout or stderr

[Volker Simonis]

Yes, you're right. I've reverted the extra fix in place as Paul suggested.

Thanks a lot for reviewing,
Volker

On Tue, Jul 6, 2021 at 6:11 PM Andrew Hughes <gnu.andrew at redhat.com> wrote:
>
> On 21:36 Tue 01 Jun     , Volker Simonis wrote:
> > Hi,
> >
> > can I please get a review for this backport?
> >
> > This change initially went into jdk 13 and has already been downported
> > to jdk 11u more than a year ago. But as jdk8u is still used a lot and
> > increasingly in containerized environments I think it still makes a
> > lot of sense to downport it to jdk 8u as well.
> >
> > If the JVM crashes in a containerized environment with its ephemeral
> > file system it becomes impossible to do any post mortem analysis of
> > the problem. In such situations the ability to dump the hs_err file to
> > stdout/stderr is very useful, because many container environments log
> > the stdout/stderr stream by default.
> >
> > Original issue: https://bugs.openjdk.java.net/browse/JDK-8220786
> > Original CSR: https://bugs.openjdk.java.net/browse/JDK-8220787
> > Original change: http://hg.openjdk.java.net/jdk/jdk/rev/cf75ea6af695
> >
> > jdk11 backport: https://bugs.openjdk.java.net/browse/JDK-8238531
> > jdk11 CSR: https://bugs.openjdk.java.net/browse/JDK-8238532
> > jdk11 change: https://hg.openjdk.java.net/jdk-updates/jdk11u/rev/783a56f3ac1f
> >
> > jdk8 backport: https://bugs.openjdk.java.net/browse/JDK-8268055
> > jdk8 CSR: https://bugs.openjdk.java.net/browse/JDK-8268058
> > jdk8 webrev: http://cr.openjdk.java.net/~simonis/webrevs/2021/8220786-jdk8u/
> >
> > I had to do quite some, but trivial changes to the jdk 11 backport
> > (which I started with) to fit it into jdk 8u:
> >
> > arguments.cpp
> > -------------------
> > In jdk 11 "FLAG_SET_CMDLINE(boolean, ...)" expands to "JVMFlag::Error
> > boolAtPut(JVMFlagsWithType flag, bool value, JVMFlag::Flags origin)"
> > which returns a "JVMFlag::Error" and can be checked for success. In
> > jdk 8,  "FLAG_SET_CMDLINE(boolean, ...)" expands to "void
> > boolAtPut(CommandLineFlagWithType flag, bool value, Flag::Flags
> > origin)" which returns void, so there's nothing to check for...
> >
> > vmError.cpp
> > ----------------
> > I think the initial implementation has a bug in the following code:
> >
> > -    if (fd_log != -1) {
> > +    if (fd_log > 3) {
> >        close(fd_log);
> >
> > I think the intention is to close the log stream if it was not stdout
> > (i.e. "1") or stderr (i.e. "2") but it checks for "fd_log > 3".
> >
> > I've fixed this in the downport but I'm happy to revert the fix if
> > somebody has a good explanation for the original code:
> >
> > -    if (log.fd() != defaultStream::output_fd()) {
> > +    if (log.fd() > 2) {
> >
> > ErrorFileRedirectTest.java
> > ---------------------------------
> > - path/package shuffling for the test library
> > - use "Platform.isDebugBuild()" instead of "@requires (vm.debug ==
> > true)" which is not supported in jdk8
> > - remove "-XX:-CreateCoredumpOnCrash" option because it doesn't exist in jdk 8
> > - use "-XX:ErrorHandlerTest=12" instead of "-XX:ErrorHandlerTest=14"
> > because "14" is not available in jdk 8. But "12" still generates a
> > SIGSEV by reading from memory address 0.
> > - check for "T H R E A D" in the output because jdk 8 has no "S U M M
> > A R Y" section.
> >
> > The jdk 8 CSR (https://bugs.openjdk.java.net/browse/JDK-8268058) has
> > been reviewed and waits for approval.
> >
> > Thank you and best regards,
> > Volker
> >
>
> Thanks for the comprehensive log of the changes needed for 8u.
>
> I assume you rolled back the local change to > 2 as Paul suggested, as I
> don't see it in:
>
> https://cr.openjdk.java.net/~simonis/webrevs/2021/8220786-jdk8u/hotspot.changeset
>
> That seems the right thing to me. This should be handled under its own bug.
>
> That changeset can be considered reviewed and approved.
>
> Thanks,
> --
> Andrew :)
> Pronouns: he / him or they / them
> Senior Free Java Software Engineer
> OpenJDK Package Owner
> Red Hat, Inc. (http://www.redhat.com)
>
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