Re: How to get the whole information dumped from kernel

Re: How to get the whole information dumped from kernel

[Park Lee]

On  Sat, 11 Dec 2004 at 10:53, Linus Torvalds wrote:
>
> - for one-off things where you don't want to go to
the bother, but
> just want to find one problem, you can do:
>      [snipped]     
>    - disable CONFIG_CALLSYM, which makes the oops
much harder to
>      read, but also more compact. Then look up the
addresses by hand
>      with "gdb vmlinux" or use the ksymoops program.
>
 
Thank you.
 
In /usr/src/linux/.config, we can see that
"CONFIG_KALLSYMS=y" is included in the General setup
section like the following: 
 
#
# General setup
#
CONFIG_SWAP=y
CONFIG_SYSVIPC=y
CONFIG_POSIX_MQUEUE=y
CONFIG_BSD_PROCESS_ACCT=y
CONFIG_SYSCTL=y
CONFIG_AUDIT=y
CONFIG_AUDITSYSCALL=y
CONFIG_LOG_BUF_SHIFT=17
CONFIG_HOTPLUG=y
# CONFIG_IKCONFIG is not set
# CONFIG_EMBEDDED is not set
CONFIG_KALLSYMS=y
CONFIG_FUTEX=y
CONFIG_EPOLL=y
CONFIG_IOSCHED_NOOP=y
CONFIG_IOSCHED_AS=y
CONFIG_IOSCHED_DEADLINE=y
CONFIG_IOSCHED_CFQ=y
CONFIG_CC_OPTIMIZE_FOR_SIZE=y
 
But, when we run 'make menuconfig', we can only see
that the General setup section only contains the
following items:
  
  [*] Support for paging of anonymous memory (swap)   

  [*] System V IPC                                 
  [*] POSIX Message Queues                         
  [*] BSD Process Accounting                          
   
  [*] Sysctl support                                  
     
  [*] Auditing support                                
     
  [*]   Enable system-call auditing support           
      
  (17) Kernel log buffer size (16 => 64KB, 17 =>
128KB)        
  [*] Support for hot-pluggable devices               
          
  [ ] Kernel .config support                          
         
  [ ] Configure standard kernel features (for small
systems)  ---> 
  [*] Optimize for size                               
 
Then, It seems that there is no place to disable
CONFIG_KALLSYMS (i.e. turn 'CONFIG_KALLSYMS=y' to
'CONFIG_KALLSYMS is not set'), How can I turn off the
'CONFIG_KALLSYMS' item?? Is CONFIG_KALLSYMS=y set
automatically by system?

Thanks,



=====
--
Best Regards,
Park Lee <parklee_sel@yahoo.com> 
 







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Re: How to get the whole information dumped from kernel

[Randy.Dunlap]

Park Lee wrote:
> On  Sat, 11 Dec 2004 at 10:53, Linus Torvalds wrote:
> 
>>- for one-off things where you don't want to go to
> the bother, but
>>just want to find one problem, you can do:
>>     [snipped]     
>>   - disable CONFIG_CALLSYM, which makes the oops
> much harder to
>>     read, but also more compact. Then look up the
> addresses by hand
>>     with "gdb vmlinux" or use the ksymoops program.
>  
>  
> In /usr/src/linux/.config, we can see that
> "CONFIG_KALLSYMS=y" is included in the General setup
> section like the following: 
>  
> #
> # General setup
> #
> CONFIG_SWAP=y
> CONFIG_SYSVIPC=y
> CONFIG_POSIX_MQUEUE=y
> CONFIG_BSD_PROCESS_ACCT=y
> CONFIG_SYSCTL=y
> CONFIG_AUDIT=y
> CONFIG_AUDITSYSCALL=y
> CONFIG_LOG_BUF_SHIFT=17
> CONFIG_HOTPLUG=y
> # CONFIG_IKCONFIG is not set
> # CONFIG_EMBEDDED is not set
> CONFIG_KALLSYMS=y
> CONFIG_FUTEX=y
> CONFIG_EPOLL=y
> CONFIG_IOSCHED_NOOP=y
> CONFIG_IOSCHED_AS=y
> CONFIG_IOSCHED_DEADLINE=y
> CONFIG_IOSCHED_CFQ=y
> CONFIG_CC_OPTIMIZE_FOR_SIZE=y
>  
> But, when we run 'make menuconfig', we can only see
> that the General setup section only contains the
> following items:
>   
>   [*] Support for paging of anonymous memory (swap)   
> 
>   [*] System V IPC                                 
>   [*] POSIX Message Queues                         
>   [*] BSD Process Accounting                          
>    
>   [*] Sysctl support                                  
>      
>   [*] Auditing support                                
>      
>   [*]   Enable system-call auditing support           
>       
>   (17) Kernel log buffer size (16 => 64KB, 17 =>
> 128KB)        
>   [*] Support for hot-pluggable devices               
>           
>   [ ] Kernel .config support                          
>          
>   [ ] Configure standard kernel features (for small
> systems)  ---> 

Right here, press Y and the press Enter and more options
(including KALLSYMS) will appear for you to make.

>   [*] Optimize for size                               
>  
> Then, It seems that there is no place to disable
> CONFIG_KALLSYMS (i.e. turn 'CONFIG_KALLSYMS=y' to
> 'CONFIG_KALLSYMS is not set'), How can I turn off the
> 'CONFIG_KALLSYMS' item?? Is CONFIG_KALLSYMS=y set
> automatically by system?

-- 
~Randy

Re: How to get the whole information dumped from kernel

[Park Lee]

On Sat, 11 Dec 2004 at 10:53, Linus Torvalds wrote:
> On Fri, 10 Dec 2004, Park Lee wrote:
> >
> > These information is the last portion of the 
> > whole information dumped from kernel on the 
> > screen. But because the machine has crashed so 
> > badly that I cann't get the whole information 
> > back.
> > Then, would you please tell me how can I get the 
> > whole information dumped from kernel when the 
> > kernel crashed? (I think that only get the whole 
> > information, Can I know what the wrong is exactly 
> > and solve it.)
>
> Several approaches:
>  - serial console ends up being very useful if you 
> do a lot of this - you can log everything to 
> another machine.
>  (And in some cases "netconsole" can be an easier 
> alternative, see 
> Documentation/networking/netconsole.txt for more 
> details).

Thanks.

I've tried to use netconsole, but it did not work very
well in my case. 
So, I want to try serial console. I have 2 computers,
one is a PC, and the other is a Laptop. Unfortunately,
my Laptop doesn't have a serial port on it. But then,
the each machine has a internal serial modem
respectively.
Then, can I use a telephone line to directly connect
the two machines via their internal modems (i.e. One
end of the telephone line is plugged into The PC's
modem, and the other end is plugged into The Laptop's
modem directly), and let them do the same function as
two serial ports and a null modem can do? If it is,
How to achieve that?

Thank you.

=====
--
Best Regards,
Park Lee

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Re: How to get the whole information dumped from kernel

[Park Lee]

On Tue, 14 Dec 2004 at 08:04, Randy.Dunlap wrote:
> Park Lee wrote:
> > [snipped]
> > [ ] Configure standard kernel features (for small
> > systems)  ---> 
>
> Right here, press Y and the press Enter and more 
> options (including KALLSYMS) will appear for you to 
> make.

Just now, I had a try. BUT there is no more options
(including KALLSYMS) appear as what you said at all!
What's the matter? ( I'm using Fedora Core 2, the
Linux kernel version is 2.6.5).

Thank you.



=====
Best Regards,
Park Lee

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Re: How to get the whole information dumped from kernel

[Randy.Dunlap]

Park Lee wrote:
> On Tue, 14 Dec 2004 at 08:04, Randy.Dunlap wrote:
> 
>>Park Lee wrote:
>>
>>>[snipped]
>>>[ ] Configure standard kernel features (for small
>>>systems)  ---> 
>>
>>Right here, press Y and the press Enter and more 
>>options (including KALLSYMS) will appear for you to 
>>make.
> 
> 
> Just now, I had a try. BUT there is no more options
> (including KALLSYMS) appear as what you said at all!
> What's the matter? ( I'm using Fedora Core 2, the
> Linux kernel version is 2.6.5).

Hi,
I can't say about FC2 in particular, but in looking
at 2.6.5 from kernel.org, it looks like this:

[*] Remove kernel features (for embedded systems)  --->

{enable above and press Enter, then see this:}

[*]   Load all symbols for debugging/kksymoops (NEW)

{enable above and save it}

Hope that helps, if not, please try (send) again.

-- 
~Randy