* Marc Haber (mh+linux-kernel@xxxxxxxxxxxx) wrote: > On Sat, Apr 23, 2016 at 06:04:29PM +0200, Borislav Petkov wrote: > > On Thu, Apr 21, 2016 at 10:04:33PM +0200, Marc Haber wrote: > > > Yes, but there are two symptoms. The VM either suffers file system > > > issues (garbage read from files, or an aborted ext4 journal and > > > following ro remount) or it stops dead in its tracks. > > > > Stops dead? What does that mean exactly? Box is wedged solid and it > > doesn't react to any key presses? > > No ping, no reaction on serial console, no reaction on virtual > console, no syslog entries. > > > Because if so, this could really be a DRAM going bad and a correctable > > error turning into an uncorrectable. How old is the DRAM in that box? > > Judging by your CPU, it should be a couple of years... > > Uncorrectable errors would still be identified by the ECC hardware, > and the box wouldn't be perfectly fine with an "old" kernel. Hmm, your problem does sound like bad hardware, but.... If you've got a nice reliable crash, can you try turning transparent huge pages off on the host; echo never > /sys/kernel/mm/transparent_hugepage/enabled Dave > > > The box reports about one correctable error per week, so I probably > > > have a faulty DIMM, but since the issue only surfaces in VMs while the > > > host system is in perfect working order... > > > > So it could be that correctable error turns into an uncorrectable one at > > some point. But then you should be getting an exception... > > Yes, that would be in the logs. > > > > And yes, I am pondering to simply replace the box with an Intel CPU. > > > > Your CPU is fine, from what I've seen so far. > > But we still postulate that the issue does only show on older AMD > CPUs. Otherwise, I wouldn't be the only one making this experience. > > > > I go the way of Debian packages since it is easier to handle the > > > crypto file systems when the machine is booting up. > > > > As long as you're testing the correct bisection kernels... > > I am reasonably sure about that, yes. > > > > And yes, I think about doing a test reinstall on unencrypted disk to > > > find out whether encryption plays a role, but I currently need the > > > machine to urgently to take it out of serice for half a month, and, > > > again, the host system is in perfect working order, it is just VMs > > > that barf. > > > > Yeah, I can't reproduce it here and I have a very similar box to yours > > which is otherwise idle, more or less. > > > > Another fact which points to potentially DIMM going bad... > > Do you want me to memtest for 24 hours? > > Greetings > Marc > > -- > ----------------------------------------------------------------------------- > Marc Haber | "I don't trust Computers. They | Mailadresse im Header > Leimen, Germany | lose things." Winona Ryder | Fon: *49 6224 1600402 > Nordisch by Nature | How to make an American Quilt | Fax: *49 6224 1600421 -- -----Open up your eyes, open up your mind, open up your code ------- / Dr. David Alan Gilbert | Running GNU/Linux | Happy \ \ dave @ treblig.org | | In Hex / \ _________________________|_____ http://www.treblig.org |_______/ -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
