Bug#676979: sbcl: (gc :full t) has no effect under certain circumstances on x86 arch

[Faheem Mitha]

Package: sbcl
Version: 2:1.0.56.0-1
Severity: normal


Please see my report at https://bugs.launchpad.net/sbcl/+bug/1009267

At this time it is not clear whether this bug is Debian-specific, but
it would be nice if someone could independently confirm it.

So far I have personally reproduced it on 2 different x86 Debian
squeeze installations, and someone else was able to reproduce it on
x86 Ubuntu. I have not been able to reproduce it on a 64 bit machine.

Brief reproduction recipe follows.

                                                     Regards, Faheem

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Installing a recent version of sbcl (1.0.56 or 1.0.57 or from the git
repos) and any version of rlwrap, basically. rlwrap is optional, but
gives readline capability, without which using command-line sbcl is
unbearably annoying. The git repos would be good, but you need a
recent version of sbcl to compile it anyway, so might as well start
with a binary package.

Then run

rlwrap sbcl

* (compile-file "nik.lisp")

* (load *)

* (main 10000)

You can get nik.lisp from the bug report. Then see if it crashes.
This crashes on my home machine and my laptop as well with a out of
heap error. Both 32 bit Debian with 2.6.32. Either way, try running

* (room)

* (gc :full t)

alternately and repeatedly. If things are working correctly, you would
get rid of the line like

  80,000,016 bytes for         2 simple-array-double-float objects.

fairly quickly, but this doesn't happen here. That is the main bug,
that gc doesn't work. For both my laptop and home machine this gets
stuck at 2 array objects.

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-- System Information:
Debian Release: 6.0.5
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable'), (50, 'unstable'), (50, 'testing'), (1, 'experimental')
Architecture: i386 (i686)

Kernel: Linux 2.6.32-5-vserver-686-bigmem (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages sbcl depends on:
ii  libc6                         2.11.3-3   Embedded GNU C Library: Shared lib

Versions of packages sbcl recommends:
ii  binfmt-support                1.2.18     Support for extra binary formats

Versions of packages sbcl suggests:
ii  sbcl-doc                    2:1.0.56.0-1 Documentation for Steel Bank Commo
ii  sbcl-source                 2:1.0.56.0-1 Source code files for SBCL
ii  slime                       1:20120420-2 Superior LISP Interaction Mode for

-- no debconf information