Given 2.1 and isa-serial output, set as ttyS0 for the guest VM with 9600 baud rate.
The test case is quite simple - display as much data as possible over serial console and do not hang the system. While qemu-1.1 works perfectly, with complaining for lost interrupts (known bug for used guest kernel), 2.1 just hangs after some seconds, eating up all available cpu quota. Test case is 'while true; dmesg; done' in serial console. I`d like to ask to consider this bug as very serious as VM going completely unresponsive in matter of tens of seconds and there are a lot of side attacks to produce enough number of printk() to the ttyS0 with serial console being set up and default settings for almost any distro in such a way that message suppression would not work and VM can be DoSed by an unprivileged user.
