Subj : Re: Crash during compilation
To   : netscape.public.mozilla.jseng
From : Oscar
Date : Mon Aug 23 2004 07:41 am

Hi,



I was just wondering how to go forward, should I submit a bug in Bugzilla?
Should I suggest a fix along with the bug report?



Brendan: Have you had an opportunity to check the validity of my concerns
regarding possible erroneous freeing of the tempPool, when FILO deallocating
after having invoked JS_ArenaFreeAllocation? I'm asking because I  wouldn't
want to add an invalid bug report to Bugzilla.



Best regards

Oscar





"Oscar" <osfo@home.se> wrote in message
news:zxpVc.1001$d5.8142@newsb.telia.net...
> Hi Brendan
>
> Thanks for your response...
>
> > Atoms are malloc'd, you must mean a JSAtomListElement allocated om
> > cx->tempPool.
>
> Yes sorry about that.
>
> > That is strange -- arena-pool allocation is LIFO, so there ouldn't
> > be
> > any way for an older allocation, below the mark stored in cg2mark rly
> > in the TOK_FUNCTION case of js_EmitTree, to be freed by a newer lease.
>
> Well... I have a therory... (Not that my theories are worth much, but here
> goes)...
>
> Is it not possible that the following two lines in JS_ArenaFreeAllocation
> puts us at risk of coming to this precise situation?
>
> if (pool->current == a)
>   pool->current = &pool->first;
>
> Seems rather dangerous to reset the current pointer if we
> have LILO deallocation. As I understand it, if we manage to get to a
> point in which we emit a new function body after running
> JS_ArenaFreeAllocation without having had to allocate too much on the
> tempPool we could very well risk
> purging basically our entire tempPool when cleaning up after the
> function.
>
> I'm sure this is not the problem but perhaps your response can help me
> be able to investigate my annoying crash further (it does disappear when
> instead repositioning the current pointer to the last arena in the pool)
>
> > Anyway, no a global variable is set, so something's missing from e
> > testcase -- right?
>
> You are absolutely right; the script is really not in human readable
> form, it wasn't the original script but in my efforts of making an as
small
> script as possible and still be able to reproduce the crash this was what
> ended up with :)
>
> (I wanted to make sure that nothing that I have defined in my global
> object was causing the crash)
>
> Have a nice weekend
>
> Regards
> Oscar

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