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Re: An Obscure Bug
- To: <linux-il(at-nospam)linux.org.il>
- Subject: Re: An Obscure Bug
- From: "Ermon (Eyal Sagi)" <security(at-nospam)magician.homeip.net>
- Date: Tue, 04 Dec 2001 18:56:04 +0200
- Delivered-To: linux.org.il-linux-il@linux.org.il
- In-Reply-To: <Pine.GSO.4.33.0112041734350.25960-100000@techst02.technion.ac.il>
- Sender: linux-il-bounce(at-nospam)cs.huji.ac.il
Hi,
From the manpage, -O3 turns on -finline-functions on top of the -O2 stuff,
so it seems to be caused by some near-trivial function in your code. My
best guess would go to a GCC bug, but I can't really say much more without
seeing some piece of code.
Can you at least describe the modification that stops the problem? This
might be a very good clue as to where the fault lies.
-Eyal
At 17:39 04/12/2001, Shlomi Fish wrote:
>I discovered an obscure bug which I am able to reproduce only under very
>rare circumctances. Here are the instructions for re-producing it:
>
>Download
>http://vipe.technion.ac.il/~shlomif/obscure-bug.tar.gz
>
>Unpack and type make. Then type "source test.sh" at the command line and
>press enter. Voila - a segfault.
>
>Now, "./test.sh" doesn't cause it. The program in question was written by
>me (it's version 1.11.24 of Freecell Solver), and is compiled with the
>"-O3" flag by gcc. If it's compiled with "-O2" it doesn't segfault.
>Nor does it when compiled with kgcc. Moreover, after I made a very small
>change in the program, it did not segfault either. Finally, running it
>under gdb cause it not to crash either.
>
>I'm using Mandrake 8.1 with KDE 2.2.1 and all of the up-to-current
>updates. My kernel is 2.4.13-12mdk from cooker.
>
>I'll appreciate if anyone can shed some light on the subject.
>
>Regards,
>
> Shlomi Fish
>
>----------------------------------------------------------------------
>Shlomi Fish shlomif@t2.technion.ac.il
>Home Page: http://t2.technion.ac.il/~shlomif/
>Home E-mail: shlomif@techie.com
>
>If:
>1. A is A
>2. A is not not-A
>does it imply that
>1. B is B
>2. B is not not-B
>
>
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