mbr ftbfs

[Matthias Klose]

Binary package hint: mbr

 mbr 1.1.9-2ubuntu2 ftbfs on i386 (and lpia)

[Matthias Klose (doko)]

confirmed by the buildds

[Henrik Nilsen Omma (henrik)]

Assigning FTBFS bug based on last upload.

[Henrik Nilsen Omma (henrik)]

Moving milestone to beta.

[Steve Langasek (vorlon)]

The Debian bug notes:
> It may be relevant that this build was run under an amd64 kernel, on a dual core processor.

This is correct. When building on a 32-bit system, the package builds and runs correctly. When building in a 32-bit chroot on a 64-bit system, the package fails to build with the mentioned test failures. When I copy the same failed build tree over to a 32-bit system and build with -nc, the tests succeed and the package build finishes successfully.

Old versions of the package have the same problem, this is not a recently introduced bug in either the mbr source or in the bin86 assembler.

I don't know yet whether this is a problem in the code or the testsuite.

[Colin Watson (cjwatson)]

The package tries to skip these tests on an amd64 kernel (see the KERNEL_ARCH stuff in debian/rules). Unfortunately it fails to detect this correctly because the buildds are run under linux32, which fiddles the output of 'uname -m'.

[Colin Watson (cjwatson)]

This is a little bit crazy, but what do people think of this diff as a workaround? I'm pretty sure our buildds all mount /proc, and I don't like the idea of disabling tests across the board.

[Colin Watson (cjwatson)]

Matthew Garrett pointed out that the lm flag will be present when running a 32-bit kernel on a 64-bit CPU too. Here's another attempt using linux64 instead (a bit of a double-take solution, but seems better).

[Steve Langasek (vorlon)]

looks good to me. Of course linux64 will fail on a 32-bit kernel and $(KERNEL_ARCH) will be empty, but empty doesn't match "x86_64", so it still gives the desired result.

[Soren Hansen (soren)]

No, linux64 on 32-bit kernels is a no-op. `linux64 uname -m` = "i686" on my trusty old absolutely non-64-bit laptop :)

[Colin Watson (cjwatson)]

mbr (1.1.9-2ubuntu3) gutsy; urgency=low

  * debian/rules: Use linux64 to check architecture, in order to override
    any use of linux32 that might hide the fact that the kernel is really
    64-bit and thus doesn't implement the vm86() syscall (LP: #134404).

 -- Colin Watson <email address hidden> Fri, 05 Oct 2007 02:51:08 +0100