From mboxrd@z Thu Jan  1 00:00:00 1970
Message-Id: <200104040914.CAA00691@tammananny.tiger>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] more questions
In-reply-to: Your message of "Wed, 28 Mar 0100 11:21:08."
             <20010328101459.DF9E1199C0@mail.cse.psu.edu>
From: Quinn Dunkan <quinn@envy.ugcs.caltech.edu>
Date: Wed,  4 Apr 2001 02:14:37 -0700
Topicbox-Message-UUID: 78a42c30-eac9-11e9-9e20-41e7f4b1d025


[ rog ]
> i've been bitten by that regexp problem before.  your problem is that
> the matches array is being used uninitialised.  as the documentation
> says:

Of course, you're right.  I forgot about that whole uninitialized-auto-
variables thing.  Sorry to inflict my C-ignorance on the list.

But here's something else.  I've been having my program suicide, and while
tracking it down, managed to provoke a kernel panic.  The message is:

panic: fp: status 8181  fppc=0xfa62 pc=0x80100241
ktrace /kernel/path 8010649e 80c209ac
[ lots of hex ]


It has something to do with a number >= 2147483648, which smells like integer
overflow.  But the weird thing is that the number is being stored in a double,
and then cast to a ulong (and it does look like an fpu thing).  And whether or
not it crashes the program or the kernel changes when I do things like take
unrelated code out of the link line, or change the order of events.

A tarball with a few plan9 binaries that crash my kernel every time is at

http://www.calarts.edu/~quinn/9crash.tgz

Just run '1/lua 1/crash.lua' or '2/lua 2/crash.lua' and see if your printer
catches on fire.  I tried to isolate it better, but it's tricky because the
computer keeps crashing and I don't want to hose my kfs.  And it has a
tendency to hide.  I'm interested in seeing if it happens on other systems, or
if it's something wrong with mine.

If it's not just my setup, I'll upload the source too (or if people don't want
to run some random binary off the net).



Oh, and by the way, what do people do when they want to find the definition of
a function or type?  "grep -n '^func' *.c" works if the code is formatted right,
but that still doesn't work for types.