# computer freezes when compiling kernel



## doughy (Jan 5, 2012)

My PC locks up after about 15 minutes into a kernel compile. I am dual booting with Debian and it does the same thing when I try to compile a Linux kernel. I looked around in BIOS but didn't see anything that looks like it would keep the kernel from compiling. I have two FreeBSD boxes and compiled the kernel for the faulty PC on one that works then moved the kernel over to the faulty PC and it works fine. Can I do the same thing on a good FreeBSD box with a Linux kernel and move the Linux kernel image over to the Linux box?

I'm not sure if compiling a Linux kernel on a FreeBSD box would work.


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## ctengel (Jan 5, 2012)

Personally I would try to get to the bottom of what is wrong with that box before going through the trouble of cross-compile Linux on FreeBSD.  I guess technically I don't see why it wouldn't work as long as you had all the necessary parts of a Linux build environment.  It sounds though like there is something seriously wrong hardware-wise (maybe a overheating issue) with that box, and it is triggered by the heavy load of the kernel compiles.  Can you reproduce the lock with other heavy loads?  Maybe a compile of something else big like Firefox?


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## SirDice (Jan 5, 2012)

ctengel said:
			
		

> It sounds though like there is something seriously wrong hardware-wise (maybe a overheating issue) with that box, and it is triggered by the heavy load of the kernel compiles.


Yeah, that's my first thought too. The second is memory errors. Compiling something big like the kernel pushes a lot out of the machine and any hardware issues are likely to turn up.


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## throAU (Jan 5, 2012)

Definitely sounds like hardware issues to me, you might want to download a copy of Memtest86 and verify that your hardware is OK.

As above, kernel/world compiles stress the machine a bit and given that you are having issues in both Linux and FreeBSD it is unlikely to be software related.


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## doughy (Jan 5, 2012)

I let the machine cool and a compile worked fine. Now I have a problem with booting the new kernel. It says


```
kernel panic - not synching: VFS: unable to mount root fs on unkown-block(0,0)
```

Any ideas?


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## j4r3ck (Jan 5, 2012)

Probably you haven't a /boot/initrd.img. Login as root on original kernel of your Linux system and generate it (probably by mkinitrd or mkinitramfs)


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## SirDice (Jan 6, 2012)

j4r3ck said:
			
		

> Probably you haven't a /boot/initrd.img. Login as root on original kernel of your Linux system and generate it (probably by mkinitrd or mkinitramfs)



Wrong OS dude, this is FreeBSD, not Linux.


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## ctengel (Jan 6, 2012)

doughy said:
			
		

> I let the machine cool and a compile worked fine. Now I have a problem with booting the new kernel.



It seems like based on what you're saying (didn't work initially for either OS...then let the box cool...now it works) the hardware issue is probably a cooling issue.  I would definitely look into the root cause (fan not working?  insufficient heatsink? not enough airflow?) of that issue.  I can't say whether your current issue is due to the same thing or not (i.e. fixing your hardware issue may not fix it, and you may be able to make it go away without fixing hardware), but I know from experience when you have a cooling issue all sorts of weird things happen (or worse, permanent hardware damage)


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## j4r3ck (Jan 7, 2012)

SirDice said:
			
		

> Wrong OS dude, this is FreeBSD, not Linux.



Read first post again.

He wanted to *cross*-compile *Linux* kernel under FreeBSD.


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## phoenix (Jan 7, 2012)

doughy said:
			
		

> My PC locks up after about 15 minutes into a kernel compile. I am dual booting with Debian and it does the same thing when I try to compile a Linux kernel. I looked around in BIOS but didn't see anything that looks like it would keep the kernel from compiling. I have two FreeBSD boxes and compiled the kernel for the faulty PC on one that works then moved the kernel over to the faulty PC and it works fine. Can I do the same thing on a good FreeBSD box with a Linux kernel and move the Linux kernel image over to the Linux box?
> 
> I'm not sure if compiling a Linux kernel on a FreeBSD box would work.



Sounds like you are over-heating the CPU on that box, causing the lockup.  You should look into that first.  If it is an overheat issue, fixing that would be best.


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