Subject: Re: [PATCH] Prevent OOM from killing init
To: mikpe@csd.uu.se (Mikael Pettersson)
Date: Thu, 22 Mar 2001 23:43:57 +0000 (GMT)
Cc: alan@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org
In-Reply-To: <200103222335.AAA22466@harpo.it.uu.se> from "Mikael Pettersson" at Mar 23, 2001 12:35:29 AM
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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
Sender: linux-kernel-owner@vger.kernel.org

> >How do you return an out of memory error to a C program that is out of memory
> >due to a stack growth fault. There is actually not a language construct for it
> SIGSEGV.
> Stack overflow for a language like C using standard implementation techniques
> is the same as a page fault while accessing a page for which there is no backing
> store. SIGSEGV is the logical choice, and the one I'd expect on other Unices.

Guess again. You are expanding the stack because you have no room left on it.
You take a fault. You want to report a SIGSEGV. Now where are you
going to put the stack frame ?

SIGSEGV in combination with a preallocated alternate stack maybe, but then you
still need to recover. C++ you can maybe do it with exception handling but
C doesnt really have the structure and longjmp just doesnt cut it.

Alan

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