[classlib][drlvm] Instability after adding DetachCurrentThread call in launcher

[Salikh Zakirov <sa...@gmail.com>]

Hi harmonists,

The latest combination of DRLVM and Classlib is highly instable on my
machine (Gentoo Linux/i686 Pentium 4 HT), causing smoke tests fail
frequently and in unstable manner. Fails are caused by
either incorrect memory deallocation (caught by glibc), or by
segmentation fault.

Tests worked much better just a few days ago, so I tried to bisect
commits to find the failure cause.

Bisection pointed to the commit

    Author: Oliver Deakin <ol...@googlemail.com>
    Date:   Mon Oct 15 15:20:32 2007 +0000

    [r584804] Adding DetachCurrentThread() call to main.c after
discussion on dev list:

http://mail-archives.apache.org/mod_mbox/harmony-dev/200710.mbox/%3c470F9FFB.4050109@googlemail.com%3e

Is anyone else seeing this instability?
Does anyone know what needs to be fixed in DRLVM to prevent it?

Re: [classlib][drlvm] Instability after adding DetachCurrentThread call in launcher

[Gregory Shimansky <gs...@apache.org>]

Salikh Zakirov wrote:
> Hi harmonists,
> 
> The latest combination of DRLVM and Classlib is highly instable on my
> machine (Gentoo Linux/i686 Pentium 4 HT), causing smoke tests fail
> frequently and in unstable manner. Fails are caused by
> either incorrect memory deallocation (caught by glibc), or by
> segmentation fault.
> 
> Tests worked much better just a few days ago, so I tried to bisect
> commits to find the failure cause.
> 
> Bisection pointed to the commit
> 
>     Author: Oliver Deakin <ol...@googlemail.com>
>     Date:   Mon Oct 15 15:20:32 2007 +0000
> 
>     [r584804] Adding DetachCurrentThread() call to main.c after
> discussion on dev list:
> 
> http://mail-archives.apache.org/mod_mbox/harmony-dev/200710.mbox/%3c470F9FFB.4050109@googlemail.com%3e
> 
> Is anyone else seeing this instability?
> Does anyone know what needs to be fixed in DRLVM to prevent it?

The change was supposed to affect only debugging scenarios since there 
was a bug that some JVMTI events were attempted to be sent in a thread 
that is no longer attached to VM.

I've recently discovered some worse scenarios on shutdown related also 
to glibc complaining about corrupted allocation list and various 
segfaults, but all of them are related to shutdown with JDWP agent (see 
HARMONY-5019 - it took me a night to debug assembly code in glibc and 
libgcc_s to find out why pthread_cancel crashes). The problem existed 
before Oliver's commit and isn't connected to it in any way.

Could you give some details, typical stack traces? I could at least say 
if I saw them already or not (BTW smoke tests work for me). I am also 
running Gentoo on x86 (stable) and amd64 (stable) but I have only 1 CPU 
so I don't catch all of the race conditions related to SMP.

-- 
Gregory