Intrepid random (but frequent) system freeze

[scott abernethy]

I've been experiencing total system freeze, frequently (say once every 1-4 hours), starting 25th Jan.
This system has been running intrepid since alpha 4 and has been very stable.

When a freeze occurs my X display doesn't update, no response to mouse or keyboard input, audio stops, can't ssh in, can't kill X or change tty. The only fix is to do a power reset.

I can't see anything obvious in the logs (though I'm not sure what I'm looking for). Memtest reports no problems, neither does fsck. I typically update daily, so looking at my apt log I noticed updates to X around that date. I've tried removing the proprietary ATI drivers, using the driver suggested by envyng, reconfiguring xserver-xorg, with no success.

$ uname -a
Linux pc559-ubu 2.6.27-11-generic #1 SMP Thu Jan 22 17:22:40 UTC 2009 i686 GNU/Linux

$ cat /proc/version_signature
Ubuntu 2.6.27-11.25-generic

$ lsb_release -rd
Description: Ubuntu 8.10
Release: 8.10

[mujaheddin (mujaheddin)]

exactly the same here

$ uname -a
Linux daniel-desktop 2.6.27-11-generic #1 SMP Thu Jan 29 19:24:39 UTC 2009 i686 GNU/Linux
$ cat /proc/version_signature
Ubuntu 2.6.27-11.27-generic
$ lsb_release -rd
Description: Ubuntu 8.10
Release: 8.10

have you already got it fixed?

[scott abernethy (scott.abernethy)]

Yes. As of yesterday, fully updated, I was still getting frequent crashes.

[Gerard van Drielen (gerard-van-drielen)]

I have the same problem, not as often as described here. My system freezes occasionaly, say once in two or three weeks. I always install updates when available. So far no fix.
My system is a pentium IV (HP Compaq d330 DT).

[Joseph Coffland (jcoffland)]

I also have the same problem.

uname -a
Linux kenny 2.6.27.7-custom-grsec #14 SMP PREEMPT Fri Mar 6 06:16:17 PST 2009 i686 GNU/Linux

I compiled a new kernel but I had the problem with the sock ubuntu kernel and my custom kernel was compiled from ubnutu sources + grsec anyway. Ever since an upgrade to Intrepid in January. I've been updating my packages regularly too.

I have dual monitors and an Nvida card. I was using the 180 nvidia driver but am trying 173 to see if that helps.

This is a huge problem for me. I am a heavy user and I get this at least once or twice a day lately. I've been evaluating other Distros but don't want to switch because Ubuntu has been so good up until now.

[Joseph Coffland (jcoffland)]

As I mentioned above, I was plagued by this problem but I've found a solution that has worked on two different machines with very different usage patterns. Both started having this problem after upgrade to Intrepid.

A solution occurred to me while watching a process through top that I knew was getting out of control and using up too much memory. I decided to see what would happen when it ran out rather than stop it. Once it hit about 2GiB the system froze hard. The kernel should have killed the process at some point or at least behaved in a graceful manner but instead I got the familiar lockup. I have 3GiB installed so including other processes that was probably the exact point when all my system memory ran out.

One of the two machines that had this problem had swap enabled the other did not so swap space does not seem to matter. One ran firefox all the time. The other never. and so on.

So the solution or work around. I've added two lines to the end of /etc/security/limits.conf:

* hard nproc 1000
* soft as 1500000 # 1.5GiB (depends on your total RAM)

After adding these lines you should reboot to get the change propagated to all running processes.

The first line limits the number of processes that can be created by a single user. This protects you against fork-bombs which I think do occur in some applications. Without this line your system will totally lock up if fork-bombed. Try running this example fork-bomb in your shell: ':(){ :|:& };:' without the quotes. WARNING: be prepared for a reboot if you don't have nproc limited in limits.conf. I believe some applications accidentally cause fork bombs and the OS should be able to handle them.

The second line limits the maximum amount of memory any single process can use. The number is in KiB and will depend no how much memory you have installed in your system. I would recommend setting it to about 75% of your total system memory.

I was getting crashes all the time on both machines. Since I added these lines both machines have been up for 9 days with no problems.

I suspect that firefox 3.0, pulseaudio, possibly gnome-panel and others have problems that trigger this but the OS has to be able to handle poorly behaved processes without crashing. I would be very interested to know what change caused this to start occurring. I suspect it is kernel related but xorg could also be involved.

FYI, when the crash did occur there was no relevant info in /var/log/syslog.

[Joseph Coffland (jcoffland)]

Update: This fix really works I'm now at 17 days uptime on both machines.

[Jeremy Foshee (jeremyfoshee)]

Hi scott,

This bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? Can you try with the latest development release of Ubuntu? ISO CD images are available from http://cdimage.ubuntu.com/releases/lucid.

If it remains an issue, could you run the following command from a Terminal (Applications->Accessories->Terminal). It will automatically gather and attach updated debug information to this report.

apport-collect -p linux 322563

Also, if you could test the latest upstream kernel available that would be great. It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text. Please let us know your results.

Thanks in advance.

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[Jeremy Foshee (jeremyfoshee)]

This bug report was marked as Incomplete and has not had any updated comments for quite some time. As a result this bug is being closed. Please reopen if this is still an issue in the current Ubuntu release http://www.ubuntu.com/getubuntu/download . Also, please be sure to provide any requested information that may have been missing. To reopen the bug, click on the current status under the Status column and change the status back to "New". Thanks.

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