You definitely weren't banned for posting about malloc. Posts about malloc are good! But yes, the account was banned, and I just looked through the log and I can't figure out why. The IP was banned as well, which suggests to me that your account might have gotten caught by a spam filter that had previously tagged that IP. I'm sorry. We've unbanned the account, obviously.
(If it was a spam filter, I have an idea about how to fix the problem which I haven't yet had time to get to.)
