smb@research.att.com (Steve Bellovin) writes:
> As I've mentioned, I've had some hangs with Galeon.  Briefly, the 
> problem occurs when there are many concurrent downloads happening, such 
> as when I do "open whole folder in tabs"; I can bypass the problem by 
> using a Web proxy.  Details are in pkg/24503

I think I'm zero-ing in on it.  When mozilla-gtk hangs I can see that
a resolver "A" request just went out but no reply came back in.  In
fact, I can see 3 request go out under the same UDP port.  Normally
when pages are clicked more slowly and the images all come from the
same site, the DNS requests all go out of an ever-decrementing port
number.  While, in theory, DNS has its own transaction ID (which is
unique even when galeon wedges), the fact that things wedge when a
non-unique port is used is somewhat suspicious.  I wonder if named()
is getting confused when it sees the same
src-host/dest-host/src-port/dest-port quad used for different
requests.

This jives with your observation that it doesn't happen when you use a
proxy (because you'd only ever try to resolve a single IP for one
hostname - that of the proxy.)

(This was tested on a "client" netbsd-current machine.  Testing it on
my server had so many DNS requests that it was hard to tell which
program was asking for what.  Running it on a quiet client let me pick
through the noise a bit better.)

-wolfgang