I am having several major problems with my Linux machine: Kubuntu 13.10 (recent clean installl), MSI m'board (AMD Phenom II X3 720; 8Gig RAM), NVidia GeForce GT 630 video card (using kernel module 319.60). The motherborad was recently replaced roughly 3 months ago -- a local 'repair' shop fried the original motherboard while 'diagnosing' what turned out to be a software problem. CPU, RAM, and video card all tested good, so they went into the new m'board.

Problems started about 6-8 weeks ago, with only small, occasional issues, each of which I started off trying to resolve individually.

  1. Occasionally, application windows hang, and all that is displayed is a flat, grey screen: all window decorations gone. I worked around this problem by turning off the kwin desktop effects, when I saw a message flash by as follows:

    kwin desktop effects restarted... due to graphics reset

  2. tar backups have failed to complete the last three weeks: first a "crc verify error", then a hung system, and finally a hung gzip.

  3. Numerous dmesg messages like: "BUG: CPU#2: Soft lockup in tar". After researching this problem, I'm not sure this is a bug at all... just heavy tar/gzip CPU usage?

  4. Google Chrome randomly and frequently crashing tabs with an "Aw, Snap" message. Google Enterprise team suggested a V8 engine error, but also hinted at hardware issues.

I'm trying to get a handle on what's going wrong and what to do to diagnose and resolve the problems. I'm guessing hardware? And if so, which component is most likely to be causing the problem and how do I isolate that? I'm going to be running a memtest86+, based on another post here.

  • Could be disk going south. Check /var/log/syslog for messages. – Jonathan Ben-Avraham Dec 25 '13 at 20:43
  • Thanks, Jonathan. I'll check that out after I finish the memtest86+ run. – JESii Dec 26 '13 at 4:22

Intermittent problems like these are hard to diagnose, but it does smell like a hardware problem.

memtest86+ is a good idea. Also, are you monitoring your CPU and other mainboard temperatures? I believe that overheating can cause intermittent glitches like the ones you're seeing. When your mainboard was replaced, the heatsink may not have been reconnected well to the CPU (or chipset). A cheap thing to try would be to replace the thermal interface layer between the CPU and heatsink.

If that doesn't work, then you're probably going to have to start swapping out hardware components to rule each one out. Start with the video card if you have a spare, but it sounds as though you may have failures in multiple systems, which suggests a bad mainboard. Sorry.

  • Thanks, Andrew. So far, memtest86+ v5.01 is reporting a constant 39 degrees celcius, so that looks OK to me. strangely enough, memtest86+ v4.20 reported a few errors before I started the v5.01 testing to make sure that it had properly identified the hardware. I'm going to let it run overnight and see what it has to say; so far no errors out of v5.01. – JESii Dec 26 '13 at 4:22

Bad memory! All these symptoms were apparently caused by bad memory. Memtest86+ reported errors in 5 locations (8Gigs, 2x4). Replaced with new memory, Memtest86+ ran clean for two full passes. Now running for over 12 hours and no Chrome problems, tar backup ran just fine and verified.

What I learned: Multiple symptoms? Test memory.

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