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> Debugging loadable kernel modules using KGDB, I am having problems debugging a module with KGDB over serial.
post Apr 28 2009, 12:52 PM
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Whats this Lie-nix Thing?

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I am trying to use KGDB over serial in a kernel for debugging a module. KGDB comes built-in with this kernel.
I want to debug a module. I have built the module with ‘-g3’ and ‘-O0’ options in the Makefile.
The kernel on the target machine was built on the development machine, with the source for the module in [kernel-source]/drivers/scsi/[module]/
I moved the vmlinuz, initrd, and /lib/modules/[kernel-name] over to the target machine.
The target kernel boots, waits for GDB on the host side, and responds to ‘continue’ on the host side.
I am able to SysRq+g on the target to interrupt after the module of interest has been loaded. That returns control to GDB on the host.
At that point I am able to ‘add-symbol-file [path] [.text address]’ and the symbols load successfully.
I can then set a desired breakpoint using the symbols that I am interested in.
Then I hit continue on the development machine, and that lets the target continue booting.
Once the target completes booting, I run a test program that will trip that breakpoint by using that module.
It is at this point that the target locks up, as though the breakpoint has been tripped. However, the development machine does not return the GDB prompt to me. It just stays locked up with no prompt.

Do you have any idea what the problem is?

Thanks in advance.

I Think I am using GDBMOD 2.4 from Amit Kale's site. I built the GDBMOD source and did a make install and that placed a 'gdb' in '/usr/local/bin'. I don't think that was there before, seeing as I made sure to install gdb at the time SUSE was installed.

'set solib-search-path [driver ko path]' does nothing (info sharedlibraries).
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