After executing:

simpleHTTP (getRequest "http://maps.google.com/maps/api/geocode/json?address=London&sensor=false")

GHC hangs and consumes all the CPU resources (CPU load rises to 100%).

Sample log:

C:\>ghci -v -dcore-lint
GHCi, version 6.12.3: http://www.haskell.org/ghc/  :? for help
Glasgow Haskell Compiler, Version 6.12.3, for Haskell 98, stage 2 booted by GHC version 6.10.4
Using binary package database: C:\PROGRA~1\HASKEL~1\201020~1.0\lib\package.conf.d\package.cache
Using binary package database: C:\Documents and Settings\User\Application Data\ghc\i386-mingw32-6.12.3\package.conf.d\package.cache
hiding package regex-posix-0.94.2 to avoid conflict with later version regex-posix-0.94.4
hiding package base-3.0.3.2 to avoid conflict with later version base-4.2.0.2
wired-in package ghc-prim mapped to ghc-prim-0.2.0.0-2feb0cb38f65a4827135ada88c34f3ef
wired-in package integer-gmp mapped to integer-gmp-0.2.0.1-72436e28c79d056c87cc0d2d2f9f3773
wired-in package base mapped to base-4.2.0.2-0d1804f62045e52b2e806996d84f5318
wired-in package rts mapped to builtin_rts
wired-in package haskell98 mapped to haskell98-1.0.1.1-b5196101fd7a8c42a8d53bd8033d6765
wired-in package template-haskell mapped to template-haskell-2.4.0.1-401621dedd4a5f07bfd8630247358bf5
wired-in package dph-seq mapped to dph-seq-0.4.0-be069f0bb710922a6ddd4ed2b91e3a6c
wired-in package dph-par mapped to dph-par-0.4.0-b31a0ce10b7c92126978fcc929077ad6
Hsc static flags: -static
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading package ffi-1.0 ... linking ... done.
Prelude> :module +Network.HTTP
Prelude Network.HTTP> simpleHTTP (getRequest "http://maps.google.com/maps/api/geocode/json?address=London&sensor=false")
*** Parser:
*** Desugar:
*** Simplify:
*** CorePrep:
*** ByteCodeGen:
Loading package syb-0.1.0.2 ... linking ... done.
Loading package base-3.0.3.2 ... linking ... done.
Loading package parsec-2.1.0.1 ... linking ... done.
Loading package network-2.2.1.7 ... linking ... done.
Loading package mtl-1.1.0.2 ... linking ... done.
Loading package bytestring-0.9.1.7 ... linking ... done.
Loading package Win32-2.2.0.2 ... linking ... done.
Loading package array-0.3.0.1 ... linking ... done.
Loading package old-locale-1.0.0.2 ... linking ... done.
Loading package old-time-1.0.0.5 ... linking ... done.
Loading package HTTP-4000.0.9 ... linking ... done.
*GHC hangs here*

I'm using Windows XP SP3, Haskell Platform 2010.2.0.0. No firewall or proxy restrictions.

The bug was also reported here: http://groups.google.com/group/haskell-cafe/browse_thread/thread/4e4a7e5eb92d1b81/48300428c7c10a57?lnk=gst&q=HTTP+package#48300428c7c10a57

There's a file in attachment with Wireshark's capture during the sample execution.

Note the same sample on ghc 6.12.1, haskell-network 2.2.1.7-3 on ArchLinux works just fine.