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

[Peter Wemm]

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, 16 Mar 2012 15:35:14 -0700

 2012/3/16 Russell Cattelan <cattelan at thebarn.com>:
 > -----BEGIN PGP SIGNED MESSAGE-----
 > Hash: SHA1
 >
 > On 3/16/12 3:51 PM, Peter Wemm wrote:
 >> 2012/3/16 Russell Cattelan <cattelan at thebarn.com>:
 >>> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
 >>>
 >>> On 3/16/12 11:56 AM, Peter Wemm wrote:
 >>>> On Thu, Mar 15, 2012 at 2:40 PM, Russell Cattelan
 >>>> <cattelan at thebarn.com> wrote:
 >>>>> The following reply was made to PR amd64/163710; it has been
 >>>>> noted by GNATS.
 >>>> [..]
 >>>>> Does the last patch seem acceptable?
 >>>>>
 >>>>> Can we close this issue out?
 >>>>
 >>>> Sadly not,
 >>>>
 >>>> +no-machine: + rm -f =A0 ${.CURDIR}/../../ficl/machine
 >>>>
 >>>> .. this is definitely bogus no matter what. This attempts to
 >>>> modify the source tree which may be read only, and should
 >>>> never even have a "machine->..." symlink in it to remove in the
 >>>> first place.
 >>> The sym link is created by the build of ficl for the loader. See:
 >>> boot/ficl/Makefile machine: ln -sf ${.CURDIR}/../../i386/include
 >>> machine
 >>>
 >>> Are you suggesting that is incorrect and should be fixed?
 >>
 >> No, you're reading it wrong: "ln -sf ${.CURDIR}/../../i386/include
 >> machine" creates ${.OBJDIR}/machine"
 >>
 >> Your patch does a "rm -f =A0 ${.CURDIR}/../../ficl/machine" which is
 >> in the source tree, not the obj tree, so it would never exist. =A0And
 >> if it does, then something is wrong with your build environment.
 >>
 > This is pretty easy to reproduce.
 > cd /sys/boot
 > make
 
 You don't do that without a 'make obj' first.
 
 > there will be a symlink in /sys/boot/ficl/machine that points to
 > i386/include.
 
 And this is user error.  Don't do that.
 
 --=20
 Peter Wemm - peter at wemm.org; peter at FreeBSD.org; peter at yahoo-inc.com; KI6FJV
 "All of this is for nothing if we don't go to the stars" - JMS/B5
 "If Java had true garbage collection, most programs would delete
 themselves upon execution." -- Robert Sewell