NAME    [Toc]    [Back]

     kgdb - remote kernel debugging with gdb

DESCRIPTION    [Toc]    [Back]

     Should a programmer be dissatisfied with  the  OpenBSD  kernel's internal
     debugger  ddb(4), and have appropriate hardware available, a
kernel with
     option KGDB may be built to  effect  remote  debugging  with
gdb(1) instead.

     To prepare for debugging over serial line one would:

        +o    Obtain a second system and a crossover serial cable.
        +o   Connect the systems and test the cable.
        +o   Build a  kernel  with  option  KGDB  and  makeoptions
DEBUG="-g".
        +o   Copy the resultant bsd.gdb to the control system, and
boot the
            corresponding bsd on the target system.
        +o   On the control system, run gdb  on  the  kernel  just
copied.
        +o    Issue the command "target remote /dev/<serial port>"
within gdb.
            The target system should enter kgdb at this point.
        +o   Debug as normal and  detach  when  done,  the  target
should resume
            normal operation.

SEE ALSO    [Toc]    [Back]

     gdb(1), ddb(4), options(4)

     gdb info documents and online documentation.

CAVEATS    [Toc]    [Back]

     The remote connection will introduce certain latencies a local debugger
     would not see.

     Not available on all architectures.

OpenBSD     3.6                         August      23,      2001