linux-kernel - Re: vm86 segfaults with NX bit

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Message-ID: <4925D596.3010304@zytor.com>
Date:	Thu, 20 Nov 2008 13:24:38 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Takashi Iwai <tiwai@...e.de>
CC:	Arjan van de Ven <arjan@...radead.org>,
	linux-kernel@...r.kernel.org, Luc Verhaegen <lverhaegen@...e.de>,
	Egbert Eich <eich@...e.de>
Subject: Re: vm86 segfaults with NX bit

Takashi Iwai wrote:
>>>>
>>> did the code that mapped this memory setup use PROT_EXEC ?
>> A good question...
>> Luc, Egbert, how does VESA driver handle it?
> 
> Just looking through the vesa directory of xorg-server code, PROT_EXEC
> is passed for all mappings, at least.
> 
> Please correct me if I'm looking at a wrong place...
> 

Please do an strace of the X server startup up to the point of the crash.

I am betting that PROT_EXEC is missing from an mmap(), or that it needs 
an additional mprotect().

	-hpa

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