Open MPI logo

Hardware Locality Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |  

This web mail archive is frozen.

This page is part of a frozen web archive of this mailing list.

You can still navigate around this archive, but know that no new mails have been added to it since July of 2016.

Click here to be taken to the new web archives of this list; it includes all the mails that are in this frozen archive plus all new mails that have been sent to the list since it was migrated to the new archives.

Subject: [hwloc-devel] Bug in v1.1 bitmap API
From: Bernd Kallies (kallies_at_[hidden])
Date: 2010-12-20 09:20:31


Hallo,

while browsing through the implementation of the bitmap API in hwloc 1.1
and comparing it with the cpuset API of hwloc 1.0, it turns out that
hwloc_bitmap_alloc uses malloc and leaves struct member ulongs
uninitialized, wheres 1.0 used calloc.

This leads to random bitmap content after creation with
hwloc_bitmap_alloc, depending on how system's malloc works. In addition,
these bitmaps cannot be zeroed with hwloc_bitmap_zero right after alloc.

One may check this with the call sequence

hwloc_bitmap_alloc
hwloc_bitmap_to_ulong
hwloc_bitmap_zero
hwloc_bitmap_to_ulong

I would expect that hwloc_bitmap_alloc returns a new empty bitmap, which
appears to be empty with all methods showing bitmap content, and which
can be used for logical bit manipulations without further
initialization.

I suggest to reintroduce calloc or memset in hwloc_bitmap_alloc.

Sincerely BK

-- 
Dr. Bernd Kallies
Konrad-Zuse-Zentrum für Informationstechnik Berlin
Takustr. 7
14195 Berlin
Tel: +49-30-84185-270
Fax: +49-30-84185-311
e-mail: kallies_at_[hidden]