From: Takashi Iwai <tiwai@suse.de>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
linux-kernel@vger.kernel.org, Luc Verhaegen <lverhaegen@suse.de>,
Egbert Eich <eich@suse.de>
Subject: Re: vm86 segfaults with NX bit
Date: Fri, 21 Nov 2008 12:38:42 +0100 [thread overview]
Message-ID: <s5hprkp8g1p.wl%tiwai@suse.de> (raw)
In-Reply-To: <4925D596.3010304@zytor.com>
At Thu, 20 Nov 2008 13:24:38 -0800,
H. Peter Anvin wrote:
>
> 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.
Well, it's not exactly a crash. VESA driver catches SIGSEGV in its
signal handler, spews the error messages and skips the vm86
operation. The segfault occurs during every vm86old syscall.
> I am betting that PROT_EXEC is missing from an mmap(), or that it needs
> an additional mprotect().
PROT_EXEC seems used in every mmap. But, VESA and int10 codes in
xorg is old and hard to follow for me.
Hopefully Egbert can give us a better insight...
Takashi
next prev parent reply other threads:[~2008-11-21 11:38 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-20 15:39 Takashi Iwai
2008-11-20 15:58 ` Alan Cox
2008-11-20 16:00 ` Takashi Iwai
2008-11-20 16:05 ` Takashi Iwai
2008-11-20 16:58 ` Arjan van de Ven
2008-11-20 17:01 ` Takashi Iwai
2008-11-20 17:05 ` Takashi Iwai
2008-11-20 21:24 ` H. Peter Anvin
2008-11-21 11:38 ` Takashi Iwai [this message]
2008-11-21 17:42 ` Egbert Eich
2008-11-22 10:20 ` Takashi Iwai
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