KGDB command line options not working for kernel 2.6.32
Hi all, Im using the following compile options for kernel 2.6.32 CONFIG_KGDB = y CONFIG_KGDB_SERIAL_CONSOLE = y While booting the kernel Im using the following command line options kgdboc=ttyS0, 115200 kgdbwait Neither is the kernel waiting for gdb connection nor is it sending any thing to the serial port. I tried reordering the options with kgdbwait first, but both are not working. I also tried kgdb8250 but no change. My serial console is working when I give console=ttyS0 option. So the serial interface seems to work fine. I saw this problem reported by multiple people in different forums but there seem to be no resolution. I tried all the suggestions but none works. Any help would be highly appreciated. Thanks Shaji Yusuf
Hello, * On Thu, Jun 23, 2011 at 10:39:44PM -0700 Shaji Yusuf wrote:
Im using the following compile options for kernel 2.6.32 CONFIG_KGDB = y CONFIG_KGDB_SERIAL_CONSOLE = y
Same here. The only difference: It is not a vanilla 2.6.32, but a Debian based 2.6.32-5-686 with only these things changed.
While booting the kernel Im using the following command line options
kgdboc=ttyS0, 115200 kgdbwait
Do you have the space between "," and "115200"? I use: kgdboc=ttyS0,115200 kgdbwait It works as expected.
I tried reordering the options with kgdbwait first, but both are not working.
I order for kgdbwait to work, it must be after kgdboc. That's what I found out the hard way. ;)
I also tried kgdb8250 but no change.
This one is wrong for 2.6.32.
Any help would be highly appreciated.
Other than the space above, I do not see a big difference between your setup and mine. Perhaps, the space is the problem? Best regards Spiro. -- Spiro R. Trikaliotis http://opencbm.sf.net/ http://www.trikaliotis.net/ http://www.viceteam.org/
Sprio, thanks for the reply! I root caused the issue by undoing my modifications and debugging again. The reason why kgdbwait did not kick in was that my point of debug was much before kgdb module loading. I think kgdb cannot be used for debugging my issue as i need to debug an issue much close to console init. Is there any way I can make kgdb load a little early? As you said the space between kgdboc=ttyS0, and 115200 also does matter. :) Thanks Shaji ----- Original Message ---- From: Spiro Trikaliotis <ml-kernelnewbies@spiro.trikaliotis.net> To: kernelnewbies@kernelnewbies.org Sent: Fri, June 24, 2011 3:21:11 PM Subject: Re: KGDB command line options not working for kernel 2.6.32 Hello, * On Thu, Jun 23, 2011 at 10:39:44PM -0700 Shaji Yusuf wrote:
Im using the following compile options for kernel 2.6.32 CONFIG_KGDB = y CONFIG_KGDB_SERIAL_CONSOLE = y
Same here. The only difference: It is not a vanilla 2.6.32, but a Debian based 2.6.32-5-686 with only these things changed.
While booting the kernel Im using the following command line options
kgdboc=ttyS0, 115200 kgdbwait
Do you have the space between "," and "115200"? I use: kgdboc=ttyS0,115200 kgdbwait It works as expected.
I tried reordering the options with kgdbwait first, but both are not working.
I order for kgdbwait to work, it must be after kgdboc. That's what I found out the hard way. ;)
I also tried kgdb8250 but no change.
This one is wrong for 2.6.32.
Any help would be highly appreciated.
Other than the space above, I do not see a big difference between your setup and mine. Perhaps, the space is the problem? Best regards Spiro. -- Spiro R. Trikaliotis http://opencbm.sf.net/ http://www.trikaliotis.net/ http://www.viceteam.org/ _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
I have one question in this context. Should we disable optimization when building the kernel when we wish to enable kgdb or should we leave it intact. Thanks, Prabhunath On Fri, Jun 24, 2011 at 5:28 PM, Shaji Yusuf <shajiyusuf@yahoo.com> wrote:
Sprio, thanks for the reply! I root caused the issue by undoing my modifications and debugging again. The reason why kgdbwait did not kick in was that my point of debug was much before kgdb module loading. I think kgdb cannot be used for debugging my issue as i need to debug an issue much close to console init. Is there any way I can make kgdb load a little early?
As you said the space between kgdboc=ttyS0, and 115200 also does matter. :)
Thanks Shaji
----- Original Message ---- From: Spiro Trikaliotis <ml-kernelnewbies@spiro.trikaliotis.net> To: kernelnewbies@kernelnewbies.org Sent: Fri, June 24, 2011 3:21:11 PM Subject: Re: KGDB command line options not working for kernel 2.6.32
Hello,
* On Thu, Jun 23, 2011 at 10:39:44PM -0700 Shaji Yusuf wrote:
Im using the following compile options for kernel 2.6.32 CONFIG_KGDB = y CONFIG_KGDB_SERIAL_CONSOLE = y
Same here. The only difference: It is not a vanilla 2.6.32, but a Debian based 2.6.32-5-686 with only these things changed.
While booting the kernel Im using the following command line options
kgdboc=ttyS0, 115200 kgdbwait
Do you have the space between "," and "115200"? I use:
kgdboc=ttyS0,115200 kgdbwait
It works as expected.
I tried reordering the options with kgdbwait first, but both are not working.
I order for kgdbwait to work, it must be after kgdboc. That's what I found out the hard way. ;)
I also tried kgdb8250 but no change.
This one is wrong for 2.6.32.
Any help would be highly appreciated.
Other than the space above, I do not see a big difference between your setup and mine. Perhaps, the space is the problem?
Best regards Spiro.
-- Spiro R. Trikaliotis http://opencbm.sf.net/ http://www.trikaliotis.net/ http://www.viceteam.org/
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Hello Shaji, * On Fri, Jun 24, 2011 at 04:58:04AM -0700 Shaji Yusuf wrote:
I root caused the issue by undoing my modifications and debugging again. The reason why kgdbwait did not kick in was that my point of debug was much before kgdb module loading.
I think I remember "kgdb early debugging" which says to compile the kgdb I/O driver not as a module, but directly in the kernel. http://www.kernel.org/doc/htmldocs/kgdb.html#CompileKGDB might give you a hint (I did not test it, though). I also see this: "If you build the kgdb I/O driver as a loadable kernel module kgdbwait will not do anything." (http://www.kernel.org/doc/htmldocs/kgdb.html#kgdbwait) This seems to proove my above point.
I think kgdb cannot be used for debugging my issue as i need to debug an issue much close to console init. Is there any way I can make kgdb load a little early?
see above: Does thie help?
As you said the space between kgdboc=ttyS0, and 115200 also does matter. :)
HTH Spiro. -- Spiro R. Trikaliotis http://opencbm.sf.net/ http://www.trikaliotis.net/ http://www.viceteam.org/
participants (3)
-
Prabhu nath -
Shaji Yusuf -
Spiro Trikaliotis