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Re: Congratulation on Etch release



On Tue 10 Apr 2007, Bob Tracy wrote:
> 
> Other annoyances (minor, but worth mentioning):
> 
> (1) "unaligned trap" messages in the system logs for various applications.
>     I honestly don't know how or to whom these should be reported.  As far
>     as the package maintainers are concerned, the number of Alpha users
>     doesn't justify the effort to determine where the problem really lies,
>     i.e., is it related to source code constructs, or is this a problem
>     with the Alpha compilers and/or binutils?

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


Paul Slootman



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