RE: Congratulation on Etch release

["Uwe Schindler" <uwe@thetaphi.de>]

> Unaligned traps point to code needing fixing, not binutils / whatever.
> 
> > radvd (IPv6 support)?  Version 1.0-1 of that package is what's
> generating
> > most of the "unaligned trap" messages I'm seeing.
> 
> Network code often displays unaligned traps, because it does a read of
> network data, and then wants to access e.g. a 32-bit value from that;
> and typically that data is somewhere halfway a word and thus not
> aligned. The code needs to be fixed to eg. first copy the data with
> memcpy to an aligned address before accessing the value.
> 
> Tracking down where the unaligned access takes place can be done with
> gdb and the address the kernel gives. This could be reported via a bug
> report, perhaps with severity minor.  It's worth fixing, as unaligned
> traps cost performance. See also
> http://www.alphalinux.org/archives/debian-alpha/May2001/0062.html
> http://lists.debian.org/debian-alpha/2005/08/msg00051.html

The simpliest is to install the "prctl" package (which is now available for
alpha, too, as the kernels are compatible to that:
http://packages.debian.org/stable/devel/prctl ) and start the program with
prctl and set the flag to send a signal on unaligned access. The program
then coredumps and you can debug it with gdb, if you also start gdb from
prctl.