I just encountered the same exact error with a Hitachi Travelstar Z5K500 (HTS545050A7E380)!
Like you, I purchased it new, about 6 months ago.
Unlike you, I had it working fine for 6 months, until it suddenly exhibited this problem today.
Since those DMA error messages point at a hardware failure, I first didn't know whether it is the hard drive or the motherboard. But thanks to your post, I am now convinced it is a hard drive problem.
Looks like a Hitachi bad series. I now know which HDD brand is not going to replace it...
P.S. Running CentOS 6.4
Last edited by d420; 10-03-2013 at 08:13 PM.