After upgraded kernel to version 3.7.3 didn't work shutdown in my laptop via power button. When I push it I have error: EXT4-fs error: I/O buffer writing ... . Problem is with kworker process. I should be remove battery from laptop to shutdown it. Last time I've upgraded kernel to testing versio 3.7.4 and error still also yet. This problem doesn't exist when I halt my laptop from console with command "halt -p". After crash durign next boot the system run journal recovering process.