Re: In recent kernels, sysklogd cannot find map file.

On 03/11/2009, linux fan <linuxscratch_at_gmail.com> wrote:
> On 11/3/09, Alan Jenkins <alan-jenkins_at_tuffmail.co.uk> wrote:
>>
>> It's not clear that this is a problem in sysklog.
>
> ?? How not clear ??
> I showed the sections of /var/log/sys.log where sysklogd was
> restarting (rebooting)
> for various kernels. All kernels were made the same way.

Because you didn't say whether the file existed, and that would be the
most obvious reason :-). (At least if you haven't looked at the
source code).

>> ... "lfs" means "linux from scratch" ...
>
> Correct
>
>> So? Why not show us "ls -l /boot/System.map-*"? ...
>>
> jhalfs_at_lfs:/$ ls -l /boot/System.map-*
> -rw-r--r-- 1 root root 781700 2009-10-31 20:25 /boot/System.map-2.6.18.8
> -rw-rw-r-- 1 root root 883331 2009-10-28 16:31
> /boot/System.map-2.6.18.8.prev
> -rw-r--r-- 1 root root 851104 2009-11-01 22:14 /boot/System.map-2.6.22.19
> -rw-r--r-- 1 root root 878798 2009-11-02 19:09 /boot/System.map-2.6.26.4
> -rw-r--r-- 1 root root 878894 2009-11-02 20:24 /boot/System.map-2.6.26.6
> -rw-r--r-- 1 root root 878950 2009-11-02 21:22 /boot/System.map-2.6.26.8
> -rw-r--r-- 1 root root 898042 2009-11-02 18:24 /boot/System.map-2.6.27
> -rw-r--r-- 1 root root 1023832 2009-11-02 13:09 /boot/System.map-2.6.31.5
>
>> ... And tell us how you
>> install your kernels?
>
> tar -xf linux-2.6.27.tar.bz2
> cd linux-2.6.27
> make mrproper
> cp -v /boot/oldconfig-2.6.27 .config
> make
> make modules_install
> cp -v arch/x86/boot/bzImage /boot/lfskernel-2.6.27
> cp -v System.map /boot/System.map-2.6.27
> cp -v .config /boot/config-2.6.27
>
> In fact, I spent a lot of time compiling kernels to confirm that the problem
> does not begin before linux-2.6.27. The problem continues through every
> kernel
> up through 2.6.31.5.
>
> If need more info, please ask.
>

Ok. I don't maintain sysklogd, but looking at the webcvs, I think the
answer is that linux no longer includes the "Version_nnnn" symbol,
which sysklogd was relying on.

The error sounds pretty harmless. System.map used to be used to
resolve symbols in crash messages. Nowadays the kernel includes
kallsyms by default, and resolves the symbols itself.

I don't see this error myself. It seems the distribution I use has
switched to rsyslog, which is somewhat more actively maintained. I
would treat this error as evidence that sysklogd is bitrotting and you
should consider an alternative :-).

Alan
Received on Tue Nov 03 2009 - 17:35:53 CET