2009-08-25 11:22:32     KGDB not working

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2009-08-25 11:22:32     KGDB not working

V Hemanth Kumar (INDIA)

Message: 79206   




I am trying to debug the kernel driver, I planned to use KGDB instead of using printk.

I am working on a custom board (BF527 core) and using KGDB over ethernet.

I followed the steps mentioned in the below link:



I have properly set the bootargs to "console=ttyBF0,57600 kgdboe=@,@".


I download and booted the uImage from u-boot.

1. When the kernel boots I just get the below log:

"Kernel command line: console=ttyBF0,57600 kgdboe=@,@"


But I don't get the remaining logs:

kgdboe: local port 6443                                                                                                  

kgdboe: local IP                                                                                            

kgdboe: interface eth0                                                                                                   

kgdboe: remote port 6442                                                                                                 

kgdboe: remote IP                                                                                           

kgdboe: remote ethernet address ff:ff:ff:ff:ff:ff


Are these messages mandatory? If so what is wrong with my kernel configuration for kgdb?


2. After this I start the gdb on my host i.e., bfin-elf-gdb vmlinux. But when I enter "target remote udp:" I get the below error:-



warning: The remote protocol may be unreliable over UDP.

Some events may be lost, rendering further debugging impossible.

Remote debugging using udp:

Remote communication error: Connection refused.



What could be the possible reasons for this?

I am using a cross cable  I mean I am directly connecting the board to my host PC.


Am I doing anything wrong, please guide.









2009-08-25 11:33:44     Re: KGDB not working

Mike Frysinger (UNITED STATES)

Message: 79208   


i dont think we've tried kgdb too much in trunk.  if you want something stable, you should be using the latest svn branch (2009R1).




2009-08-25 12:06:39     Re: KGDB not working

V Hemanth Kumar (INDIA)

Message: 79209   


Hi Mike, can I download the tarred image of the 2009R1 SVN branch?

In my company I have proxy so I cannot download using SVN client, is there any other way to download it. I have followed steps mentioned in   docs.blackfin.uclinux.org/doku.php?id=version_control_systems but no luck.






2009-08-25 12:27:27     Re: KGDB not working

Mike Frysinger (UNITED STATES)

Message: 79210   


2009R1 has been released




2009-08-25 12:30:56     Re: KGDB not working

Patrick Doyle (UNITED STATES)

Message: 79211    WOO HOO!!!! How did I miss that?!?!?








2009-08-25 23:17:36     Re: KGDB not working

Sonic Zhang (CHINA)

Message: 79214   


Don't forget to configure proper IP before you connect to kgdb. You can add IP=xxx.xxx.xxx.xxx to bootargs in uboot.




2009-08-27 01:02:04     Re: KGDB not working

V Hemanth Kumar (INDIA)

Message: 79267   


thanks for the suggestions, the KGDB works for the 2009R1 release!


But out of curiosity I want to know, why KGDB is not working on the trunk versions? Is it that standard releases are done from the branch folder and all experiments done on the trunk one?




2009-08-27 01:39:01     Re: KGDB not working

Mike Frysinger (UNITED STATES)

Message: 79268   


that is pretty much how all scm development occurs


we'll look at trunk at some point to make sure it works