[Webkit-unassigned] [Bug 102828] r134080 causes heap problem on linux systems where PAGESIZE != 4096

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=102828





--- Comment #7 from Filip Pizlo <fpizlo at apple.com>  2012-11-27 03:49:44 PST ---
(In reply to comment #3)
> (In reply to comment #2)
> > (From update of attachment 175259 [details] [details])
> > View in context: https://bugs.webkit.org/attachment.cgi?id=175259&action=review
> > 
> > I'm somewhat confused as to why a different page size makes things segfault. Where exactly did it segfault? I wouldn't be opposed to making the Region size variable, e.g. 16 * WTF::pageSize() or something like that.
> I don't know where exactly the error comes from (it varies by tests, debug/release) but it always happens in a heap operation since r134080. This patch fixed the problem.

I don't like the idea of doing a blind fix.  Can you try to do more investigation into where in our memory management logic things go wrong?

It would be good to understand this.  It may even be that you've found a more fundamental bug that happens to only show up with larger page sizes, but is just harder to spot with the usual page sizes that most WebKit clients use.

> 
> > > Source/JavaScriptCore/heap/MarkStack.cpp:48
> > > +#if OS(LINUX) && COMPILER(GCC)
> > 
> > Instead of putting a bunch of nasty ifdefs everywhere, maybe you could use WTF::pageSize()?
> Would be better but I cannot test in on windows and a WTF::pageSize() should be multi platform I guess. I will try to add a WTF::pageSize() implementation for Linux.

-- 
Configure bugmail: https://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.