On Mon, Mar 12, 2001, Aviram Jenik wrote about "FTP hangs, taking 100% CPU":
> It can even continue to 'run' for days, even though the FTP client is long
> gone. What's worse, it takes 100% CPU, and if a second connection is
> initiated, a second process remains with an additional 100% CPU (and this
> really takes the fun out of our 2 CPU machine).
>
> The whole thing is very strange, since there's no problem with any FTP
> clients besides this one, and there's nothing special about our FTP daemon
> (wu-ftpd-2.6.0).
> Does anybody have a clue about what might be causing this?
I've seen this happen on an FTP server that runs (among other things)
ftp.ivrix.org.il. It is running wu-ftpd-2.6.1(2), and roughly once in two
weeks an FTP process hangs like you describe, wasting CPU until I kill it.
I could never find out what is causing this, or when it happens (I didn't
notice what kind of client causes this, because ftp doesn't have a user-agent
capability like HTTP).
I never saw this problem in the previous version I had installed (2.6.0),
but maybe it's just a coincidence - it certainly looks like the same problem
you describe. It's quite likely an wu-ftpd bug - now that you know how to
recreate the problem (I never could), perhaps you should file a bug report
with wu-ftpd? (or debug it yourself!). No matter how buggy or misbehaving a
client is (if it is at all), it shouldn't cause the server to hang in a
tight loop, because that is a denial-of-service risk.
--
Nadav Har'El | Tuesday, Mar 13 2001, 18 Adar 5761
[EMAIL PROTECTED] |-----------------------------------------
Phone: +972-53-245868, ICQ 13349191 |The socks in my drawer are like
http://nadav.harel.org.il |snowflakes: No two are alike.
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