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Message-ID: <s5hprkp8g1p.wl%tiwai@suse.de> Date: Fri, 21 Nov 2008 12:38:42 +0100 From: Takashi Iwai <tiwai@...e.de> To: "H. Peter Anvin" <hpa@...or.com> 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 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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