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Bug#277884: xserver-xfree86: X segfaults on AMD64 with noexec enabled



severity 277884 important
merge 277699 277884
thanks

On Sat, Oct 23, 2004 at 02:29:28AM -0300, Peter Cordes wrote:
>  background:  AMD64 NX support works in 32bit and 64bit mode.  It adds an
> exec permission bit to PAE page tables, so PROT_READ is separate from
> PROT_EXEC.  Since it only works with 3rd level page tables, not plain x86
> ones, it only works with highmem64GB kernels (in which case it's on by
> default).
> 
> see http://lists.debian.org/debian-amd64/2004/09/msg00393.html
> http://kerneltrap.org/node/view/3240/9418
> 
>  Summary: noexec means memory pages have to be mapped with PROT_EXEC if you
> want to run code in them.  Stack and heap are non-executable by default.
> Apparently ELF executables can specify executability of things...
> 
>  The bug is that X segfaults on noexec kernels, but not when I boot with
> noexec=off.  This happens with the radeon driver, and with the ati driver
> (on a dual Opteron Tyan board with built-in mach64 video.)
> 
>  Please make the i386 xserver-xfree86 package work on NX systems.  (The
> kernels that Debian ships aren't compiled with highmem64, so this will only
> affect people who recompile their kernels, not everyone who installs Sarge
> on an AMD64.  In that case this bug would be "important".)

Is there a reason you didn't submit this information as follow-up to
#277699?

-- 
G. Branden Robinson                |     The last time the Republican Party
Debian GNU/Linux                   |     was on the right side of a social
branden@debian.org                 |     issue, Abe Lincoln was president.
http://people.debian.org/~branden/ |     -- Kirk Tofte

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