# Had a couple random hard lockups need help on how to trace

## bobspencer123

So I have had 3 hard lockups in the past three days. I hadn't had a lockup in a long time prior to this. The weird thing is that the computer has locked up when I was away. The only thing really actively running was transmission bt client. 

I really want to know if there are any logs or programs I can install to trace hard lockups. Because by the time I reboot dmesg doesn't have any of the old info. 

Also before you ask I tried to ssh into my box but that doesn't even work only a manual cold restart works.

Thanks!

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## NeddySeagoon

bobspencer123,

Did the ATX power button work or did you have to switch off the mains supply ?

If the latter, you have experienced a double bus fault and the CPU entered the halt state. Thats game over.

It won't exit halt even for interrupts, like the power button.

If the power button worked, you didn't get a double bus fault. The CPU was still halted but was able to respond to interrupts.

Lockups of both types are usually hardware related and usually leave nothing in logs, as there is no warning and no CPU cycles to flush any log to disk.

Start with memtest.  A failure indicates a problem but not always RAM.

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## bobspencer123

Thanks for the info Neddy. I was able to poweroff using the reset button on the box (did not have to disconnect power supply). 

I'm hoping that it's X related and not hardware related but I will run memtest to check ram at least.

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## NeddySeagoon

bobspencer123,

The reset button does a hard reset - it pulls the #reset line low and the CPU does a restart as it would from power up, so we still don't know how hard your lockup was.

Reset is not the ATX power on/off switch

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## bobspencer123

well I ran memtest86+ and the first thing I discovered was that my ram timings were not set to what they "should" be according to the manufacturers specs. So I reset them and let the test run for a couple cycles without issues. I haven't had a hard lockup since (but it's only been a day and will post back again if I do with any new information.

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## NeddySeagoon

bobspencer123,

What were your RAM timings ?

What are they now ?

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## bobspencer123

 *NeddySeagoon wrote:*   

> bobspencer123,
> 
> What were your RAM timings ?
> 
> What are they now ?

 

I forget what they were (were set on auto in bios) they are now 5-5-5-15 according to specs on newegg for ram.

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## NeddySeagoon

bobspencer123,

Auto means read the settings from the Serial Presence Detect ROM on the stick of RAM.

Thats programmed by the manufacturer as a part of the build of the RAM, so its unlikely to be wrong.

I am aware of some motherboards not doing the properly, so you may be onto something.

This ROM contains timings and a lot of other information about the RAM.

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## bobspencer123

Well it locked up at 4:41 a.m. last night again. I booted with system rescue cd to check the logs and nothing unusual really stood out to me. 

The only thing (besides hardware failure) that I can think of is that I recently started using iptables for extra protection (I'm behind a router anyways). I wonder if something with iptables is causing the lockup. I doubt this but it is the only major change that has occurred in my system recently besides normal updating. 

I guess my next step will be to use the UBCD and the Hutil utility from Samsung to test my main drive (aka /boot and /) (which is approaching it's third birthday in July) Here is  link  to drive from newegg from where I bought it.

I did recently buy a 1.5 tb sata drive for storage so I could probably migrate to that if need be but would have to do some repartitioning, etc...

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