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Date: Mon, 30 Apr 2007 12:09:52 -0700
From: William Lee Irwin III <wli@holomorphy.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Andi Kleen <andi@firstfloor.org>, Alan Cox <alan@lxorguk.ukuu.org.uk>,
       David Chinner <dgc@sgi.com>, Zan Lynx <zlynx@acm.org>,
       Adrian Bunk <bunk@stusta.de>,
       Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [2/6] add config option to vmalloc stacks (was: Re: [-mm patch] i386: enable 4k stacks by default)
Message-ID: <20070430190952.GP31925@holomorphy.com>
References: <20070428191927.GN3468@stusta.de> <1177795118.7828.6.camel@localhost> <20070430035838.GC77450368@melbourne.sgi.com> <20070430091754.24df88df@the-village.bc.nu> <p73wszuyx7h.fsf@bingen.suse.de> <20070430104806.GA14944@infradead.org> <p73slaiys9v.fsf@bingen.suse.de> <20070430173819.GC19966@holomorphy.com> <20070430174310.GE19966@holomorphy.com> <20070430181104.GB14739@infradead.org>
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On Mon, Apr 30, 2007 at 10:43:10AM -0700, William Lee Irwin III wrote:
>> Add a config option to vmalloc() task stacks so that stack overflows are
>> detected without fail, and with a fatal failure mode at that.

On Mon, Apr 30, 2007 at 07:11:04PM +0100, Christoph Hellwig wrote:
> Whee, this sounds like a really helpful although costly debugging option.

If desired, I can redo it standalone.

It should be clear from the remainder of the series of debug patches
that it's readily extensible to IRQ stacks for similar purposes, as
IRQ stacks are similarly vmalloc()'d by later patches in the series.

The patch to make __pa() BUG() on vmallocspace addresses may also be
worthy of consideration in conjunction with vmalloc()'ing the stack.
That particular patch was suggested by freitag.


-- wli