PREEMPT_RT specific bugs can be reported either on the linux-rt-users mailinglist or using the Linux kernel bug tracker.
Have a look at "Mailing lists" for more linux-rt-users mailing list information.
Please add at least the following information to your bug report:
Please check first whether your problem has been reported already to avoid duplicate bug reports. If you find a matching entry select that and enter additional information if possible. Add your email address to the bug entry so you get notified about updates.
If your bug is new go to the bug reporting page and select “Alternate Trees” as product and “rt” as component. Fill in the remaining fields with the details of your problem. Please check the guidelines for bug reporting.
For more detailed information about using bugzilla, please have a look at "Using Bugzilla".