amd64/163710: setjump in userboot.so causes stack corruption

Kostik Belousov kostikbel at gmail.com
Sat Dec 31 08:17:15 UTC 2011


On Sat, Dec 31, 2011 at 03:20:10AM +0000, Peter Wemm wrote:
> The following reply was made to PR amd64/163710; it has been noted by GNATS.
> 
> From: Peter Wemm <peter at wemm.org>
> To: Russell Cattelan <cattelan at thebarn.com>
> Cc: freebsd-gnats-submit at freebsd.org
> Subject: Re: amd64/163710: setjump in userboot.so causes stack corruption
> Date: Fri, 30 Dec 2011 19:16:10 -0800
> 
>  On Fri, Dec 30, 2011 at 12:24 PM, Russell Cattelan <cattelan at thebarn.com> w=
>  rote:
>  > On 12/30/11 1:33 AM, Peter Wemm wrote:
>  >> On Thu, Dec 29, 2011 at 7:16 PM, Russell Cattelan
>  >> <cattelan at digitalelves.com> wrote:
>  >>
>  >>>> Description:
>  >>> For some reason the forth interpreter is built and linked as 32bit even
>  >>> on amd64.
>  >> That's the catch. We use the same 32 bit loader on i386 and amd64.
>  >> The common loader understands both kernel formats. =A0This unfortunately
>  >> has meant that the libstand and sys/boot environment has had to be 32
>  >> bit.
>  >>
>  > Yes this is bit of an odd situation.
>  > the loader is linked 32bit but userboot.so / libstand is built 64bit
>  > but pulls in the 32bit ficl lib.
>  > The 64bit libstand provides the setjmp call that needs 96 bytes
>  > of space but since ficl is built with the 32bit jump_buf (48 byte )
>  > structure
>  > things go sideways.
>  
>  We link the loader with the 32 bit libstand though.  It cannot work
>  any other way.  BTX is 32 bit only.
userboot.so is 64bit, and, as I already pointed the originator, it
uses the separate ficl build, sys/boot/userboot/ficl.
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