[SOLVED] Slackware Linux Essentials question - Selecting a Kernel...

chrisretusn · 01-14-2011, 09:02 AM

Quote:

Originally Posted by T3slider

The only important symlink there is System.map --> System.map-generic-smp-2.6.33.4-smp, and I'm not 100% sure whether that's needed either.

You don't need any of those symlinks IF you are specifying the exact kernel to boot from (e.g., vmlinuz-generic-smp-2.6.33.4-smp) in lilo.

Using symlinks is standard practice and make things simple.

lumak · 01-14-2011, 09:53 AM

Personally, symlinks complicate things. If all you have is one boot option, compile your own kernel, and 'install' it without copying over the files your self, you may end up with a system that doesn't boot and will need a CD to recover.

onebuck · 01-14-2011, 09:57 AM

Hi,

Quote:

Originally Posted by chrisretusn

You don't need any of those symlinks IF you are specifying the exact kernel to boot from (e.g., vmlinuz-generic-smp-2.6.33.4-smp) in lilo.

Using symlinks is standard practice and make things simple.

I will point you to ' System.map Explanation' and 'The system.map File' notes by rworkwan. Read the referenced links and then come back. You may not need it but it would be nice to have it when you do;

Quote:

excerpt from 'system.map File';Device Drivers

System.map isn't just useful for debugging kernel oopses. A few drivers need System.map to resolve symbols since they're linked against kernel headers instead of glibc). They won't work correctly without the System.map for the particular kernel currently running. This is NOT the same thing as a module not loading because of a kernel version mismatch, which has to do with the kernel version, not the kernel symbol table which changes between kernels of the same version!

Just one of many reasons that justify and provide a means to get information at times to diagnose.

Your system to do as you like but a generic statement as you put it. Not on my system!

I'll keep things clean and clear so that when problems do come up then I'll use all the tools available to help diagnosis.

T3slider · 01-14-2011, 07:56 PM

Quote:

Originally Posted by chrisretusn

You don't need any of those symlinks IF you are specifying the exact kernel to boot from (e.g., vmlinuz-generic-smp-2.6.33.4-smp) in lilo.

Using symlinks is standard practice and make things simple.

Symlinks to kernel versions are ONLY useful if you don't use LILO in my opinion. You have to run `lilo` after editing lilo.conf every time anyway, and if you change the symlink it won't work at boot-time without re-running lilo because it is referencing the inodes of the old kernel image (if it still exists). If you use GRUB, then symlinks to kernel images make things much easier. If not, then it's really no help at all.

chrisretusn · 01-16-2011, 10:03 AM

Quote:

Originally Posted by onebuck

Read the referenced links and then come back. You may not need it but it would be nice to have it when you do; Just one of many reasons that justify and provide a means to get information at times to diagnose.

Your system to do as you like but a generic statement as you put it. Not on my system!

Did you read my post?

I was replying to this:

Quote:

Originally Posted by T3slider

The only important symlink there is System.map --> System.map-generic-smp-2.6.33.4-smp, and I'm not 100% sure whether that's needed either.

What I said with this:

Quote:

Originally Posted by chrisretusn

You don't need any of those symlinks IF you are specifying the exact kernel to boot from (e.g., vmlinuz-generic-smp-2.6.33.4-smp) in lilo.

Using symlinks is standard practice and make things simple.

Exactly were in my post did I say that System.map was not needed?

One could also name the System.map file System.map-2.6.33.4-smp.

At any rate a Linux system should run just fine with out System.map symlinked. I did not advocate doing so I simply said the symlink is not needed. Please feel free to give me some specifics in which the symlink is needed to run Linux, not debug it.

Did you know in Slackware klogd does not use System.map, it hasn't for quite some time. From rc.syslog:

Code:

    echo "/usr/sbin/klogd -c 3 -x"
    # '-c 3' = display level 'error' or higher messages on console
    # '-x' = turn off broken EIP translation
    /usr/sbin/klogd -c 3 -x

The 2.6 kernel can decode most kernel oopses and produces decent dumps on it's own with out the use of System.map. Both the generic and huge kernels are built with CONFIG_KALLSYMS.

In the for what it is work department; I do symlink System.map to match my kernel.

Just for kicks, I am running another Slackware box without the kernel System.map linked, renamed to System.map or using the 'uname -r' suffix. I am keeping the standard Slackware names.

T3slider · 01-16-2011, 03:48 PM

Quote:

Originally Posted by chrisretusn

Did you know in Slackware klogd does not use System.map, it hasn't for quite some time. From rc.syslog:

Code:

    echo "/usr/sbin/klogd -c 3 -x"
    # '-c 3' = display level 'error' or higher messages on console
    # '-x' = turn off broken EIP translation
    /usr/sbin/klogd -c 3 -x

The 2.6 kernel can decode most kernel oopses and produces decent dumps on it's own with out the use of System.map. Both the generic and huge kernels are built with CONFIG_KALLSYMS.

Thanks for the full explanation; I hadn't thought to look into klogd's passed parameters and frankly didn't know you could forgo reading the System.map file. I haven't seen this information anywhere, and thus why I stated I wasn't sure if the symlink was needed. Anyway, the other symlinks are frivolous and may be helpful on a personal level but still do not definitively indicate whether or not you are using the symlinked kernel -- if one did not run an error-free lilo after editing lilo.conf the symlink may still exist, the system may boot, but they may still not be running the kernel they think they are. It is for unlikely scenarios like this that I suggested checking /proc/config.gz instead of relying on the circumstantial evidence of a symlink.