Accessing Kernel.org will simply result in a "Down for maintenance" message. It's also in a similar manner for Linux.com, which was exploited earlier this month. LinuxFoundation.org is at least back online.
On Friday, Peter Anvin issued a status update concerning the state of Kernel.org on the kernel mailing list. "As you know, we've been working very hard on building a new kernel.org infrastructure from the ground up. This new infrastructure will no longer have shell access to the git repositories; instead we will be running git using the gitolite web glue."
Due to Kernel.org switching over to Gitolite rather than shell access to repositories, most of this message describes the differences and that active kernel developers need to obtain new credentials, etc.
In terms of when Kernel.org may be back online, "We are planning to get the first trees up and running early next week with broader access happening in early October. We will be bringing up additional developer services later, as resources permit and we can do so securely."
"We understand that the kernel.org outage has inconvenienced each of you as well as the larger Linux community. And, adjusting to the new tools will take some additional time and hassle. We apologize for that. But I want to assure you that getting the kernel.org development machines back up is the highest priority of kernel.org." In the month since the attack, kernel developers have relied upon GitHub, FreeDesktop.org, and other resources for continuing Linux kernel development. At least in October this will hopefully be an issue of the past.