On 06/06/10 16:57, Willi Mann wrote: > Hi! > > I came over this bug after the latest upload of enigmail to debian. The > build only failed on mips and on mipsel, on mipsel with the message "Bus > error". > > https://buildd.debian.org/fetch.cgi?pkg=enigmail;ver=2%3A1.0.1-2;arch=mipsel;stamp=1275567604 > > The command "install-xpi" that exposes this bus error is a python script. It > uses the package python-rdflib, which is an RDF library. The parser for the > supported RDF query language is generated C code. > > I don't have shell access to a mipsel machine, so I did all my tests in qemu > using -M malta as machine type. > > The first thing I tried is to compile without optimization. The error no > longer occured. > > So I tried to reduce the largest function in the generated parser by > removing debug code first that shouldn't change the results. Unfortunately, > after the removal of one type of these debug blocks, the "Bus error" no > longer occured. > > So I did a binary search on the number of blocks I could remove before the > problem disappears. The result is that I have two versions of the parser > that only differ in 8 lines with one exposing the bug, the other not. > > The command-line is > $ gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict- > prototypes -g -O2 -fPIC -I/usr/include/python2.5 -c src/bison/SPARQLParser.c > -o build/temp.linux-mips-2.5/src/bison/SPARQLParser.o > > The two versions of the parser are available from > > http://wserver.wm1.at/~willi/debian/gcc_mipsel_bug/ > > The source package is available from > > http://packages.debian.org/source/sid/rdflib > > A stripped down version of install-xpi that's enough to trigger the bug is > available from the following Debian bug: > > http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=584327 > > It's then enough to run > $ ./install-xpi install.rdf > > to trigger the bug. > > Is this a gcc bug? Maybe, maybe not. Do you get any compiler warnings, with full warnings enabled? What is the code that faults? Andrew.
