Re: Potential bug in openjdk-11 on mips64el

On Mon, Feb 15, 2021 at 10:22 PM Aleksey Shipilev <[email protected]> wrote:
>
> On 2/15/21 1:40 AM, Olek Wojnar wrote:
> > On Sat, Feb 13, 2021 at 2:21 PM <[email protected] <mailto:[email protected]>> wrote:
> >     It selects the "Zero" VM, which I assume is the one used on mips64el.
> >     https://openjdk.java.net/projects/zero/
> >
> > Ah, thanks for the explanation! It helped me to appropriately adjust build-depends. Hmm, it looks
> > like Zero is not supported on MIPS at the moment, but perhaps that site is just out-of-date?
>
> There only Zero on mips64el for all current OpenJDKs. Zero for mips64el should be supported since
> JDK 10, see JDK-8186313: https://bugs.openjdk.java.net/browse/JDK-8186313
>
> ...so openjdk-11 is supposed to work.
>
> > On Sat, Feb 13, 2021 at 6:56 PM Tiago Daitx <[email protected]
> > <mailto:[email protected]>> wrote:
> >
> >
> >     This seems to indicate that the isDirectory call [4] is getting wrong
> >     file attributes. Following the trail, those file attributes come from
> >     a fstatat call [5] which ultimately come from the native stack in
> >     UnixNativeDispatcher.c [6]. The actual way that fstatat is called
> >     depends on the build flags and defines from the arch, so somebody with
> >     better knowledge might want to take a look at UnixNativeDispatcher.c
> >     [6] and tell if OpenJDK is picking the right function to call for
> >     mips64el.
> >
> >
> > Thanks for the excellent analysis! So is this indeed a bug in OpenJDK on mips64el then? I'm happy to
> > file the bug, referencing all of the information in this thread, if that's the probable culprit here.
>
> Thing is, there is hardly anyone who supports mips64el in OpenJDK upstream. I think Debian folks are
> the most heavy users of it :) So, while you can submit a bug upstream, I don't think there is a high
> chance anyone picks it up. You can try to ask here:
>    https://mail.openjdk.java.net/mailman/listinfo/mips-port

I would like to pick it up. However, I am on vacation at the moment
and did not have a mips64el machine on hand. If time permits, I will
return to the company in three days to follow up on this issue.

Cheers,
Ao Qi

>
> It looks to me that Zero mips64el is another instance of SecureDirectoryStream bug tail:
>    https://bugs.openjdk.java.net/issues/?jql=text%20~%20%22SecureDirectoryStream%22
>
> If there is the mips64el machine where this reproduces, the next step would be trying the mainline
> JDK NIO tests, something like:
>
>   $ git clone https://github.com/openjdk/jdk
>   $ cd jdk
>   $ wget https://builds.shipilev.net/jtreg/jtreg.zip
>   $ unzip jtreg.zip
>   $ ./configure --with-debug-level=fastdebug --with-jtreg=./jtreg
>   $ make run-test TEST=java/nio
>
> ...and if that does not yield failures, then MCVE would be needed.
>
> --
> Thanks,
> -Aleksey