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From: Andi Kleen <ak@suse.de>
To: piet@bluelane.com
Cc: "Amit S. Kale" <amitkale@linsyssoft.com>,
	"Vladimir A. Barinov" <vbarinov@ru.mvista.com>,
	Andrew Morton <akpm@osdl.org>,
	kgdb-bugreport@lists.sourceforge.net, trini@kernel.crashing.org,
	linux-kernel@vger.kernel.org
Subject: Re: linux-2.6 x86_64 kgdb issue
Date: Wed, 31 May 2006 11:41:43 +0200	[thread overview]
Message-ID: <200605311141.43340.ak@suse.de> (raw)
In-Reply-To: <1149064749.26542.191.camel@piet2.bluelane.com>


> My bet is that in this case I was storing a LOT of 
> data in the thread structure, so the space left for 
> the stack was massively reduced. 

Ok so it was your bug. Don't do that.

> Sure but the debugger environment must tolerate larger stacks.

No, Linux doesn't tolerate larger stacks.

> But this can miss a minor abuse. The interrupt check
> is a quick and simple hack but I wonder if it's really
> optimal for commercial implementations.

In practice if you overwrite thread_info you crash eventually
and it's noticed.  If you write below thread_info but keep
ti intact then the redzone would likely not catch it either.

I don't think an additional red zone would improve overflow detection 
in a significant way.

> I think all modules should be ABLE to be built in.

If you have a working module it can be easily built in too.
Just hacks that don't work with modules are bad.

-Andi

  reply	other threads:[~2006-05-31  9:41 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <446E0B4B.9070003@ru.mvista.com>
     [not found] ` <200605241240.05313.amitkale@linsyssoft.com>
     [not found]   ` <4474A1D0.30807@ru.mvista.com>
     [not found]     ` <200605251207.27699.amitkale@linsyssoft.com>
2006-05-31  4:45       ` linux-2.6 x86_64 kgdb issue Piet Delaney
2006-05-31  5:50         ` Andi Kleen
2006-05-31  6:46           ` Piet Delaney
2006-05-31  7:13             ` Andi Kleen
2006-05-31  8:39               ` Piet Delaney
2006-05-31  9:41                 ` Andi Kleen [this message]
2006-05-31 15:03               ` Tom Rini
2006-05-31 21:01                 ` Andi Kleen
2006-05-31 22:35                   ` Tom Rini
2006-05-31 22:59                     ` Andi Kleen
2006-05-31 22:52                   ` Piet Delaney
2006-05-31 23:03                     ` Piet Delaney

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