[lug] System.map

[Lynn Danielson]

Rob Riggs wrote:
> 
> "Howell, Jeff S" wrote:
> >
> > So how does one fix this?
> 
> Ah, right. A new System.map is generated in the top-level of the
> kernel source tree every time a new kernel is made. This should
> be copied into the /boot directory.

A work mate told me last week that this was recommended practice.
I've never done it.

The klogd man page says that if a symbol file is not explicitly
specified the following filenames will be tried:

       /boot/System.map
       /System.map
       /usr/src/linux/System.map           

It goes on to say that if an experimental or test kernel is 
compiled with the sources in the 'standard' location of 
/usr/src/linux the map in /boot/System.map will be bypassed
in favor of the map in /usr/src/linux/System.map.

So, is the above info no longer accurate or are there other 
dependencies on the System.map file?  If I'm reading the the
above paragraph correctly then there should be no need to copy
System.map from /usr/src/linux to /boot.  Yes/no?

Lynn Danielson
 

> I always copy my System.map to a version specific file-name and
> make a symlink. Currently my /boot/System.map looks like this:
> 
> lrwxrwxrwx   1 root     root           35 Oct 16 17:38 System.map -> ./System.map-2.2.13pre17+raid+ipsec
> 
> > -----Original Message-----
> > From: Rob Riggs [mailto:rob at pangalactic.org]
> > Sent: Monday, November 08, 1999 3:09 PM
> > To: lug at lug.boulder.co.us
> > Subject: Re: [lug] System.map
> >
> > "Stephen G. Smith" wrote:
> > >
> > > Will someone explain sysmap.map?
> > > What does it do?
> > >
> > > On a new kernel install, is a new one generated?
> > >
> > > I have a new kernel installed now and I get a message that
> > > the System.map lists the wrong kernel version..
> >
> > The System.map file lists the addresses of kernel functions and
> > static data areas, so that programs like 'ps' can determine what
> > kenrel function a process may be sleeping in. If run 'ps -aelf',
> > for instance, it lists a WCHAN column with a function name. This
> > is the function that the process is sleeping in.
> >
> > The System.map is also used to decode the traceback that the kernel
> > emits when the kernel has an exception (or "kernel oops"). The newer
> > syslogd can do this, provided a System.map is installed.
> >
> > Having a System.map installed that does not coorespond to your
> > running kernel can cause all sorts of confusion when trying to
> > track down obscure system problems.