just upgraded to kernel 3.4.3-1.fc17.x86_64 and it went panic after 2 minutes.
Now I get a kernel panic message when booting the machine:
Kernel panic - not syncing: VFS: Unable to mount root fs n unknown-block(0,0)
Pid: 1, comm: swapper/0 Not tainted 3.4.3-1.fc17.x84_64 #1
and the call trace which I'm not reporting.
Using old kernels gives me a filesystem error, requiring to ex