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Date:      Mon, 5 May 2008 09:27:10 -0700
From:      "David Christensen" <davidch@broadcom.com>
To:        "Alexander Sack" <pisymbol@gmail.com>
Cc:        "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>
Subject:   RE: Not All Symbols Present in a Loadable Kernel Module
Message-ID:  <5D267A3F22FD854F8F48B3D2B523819324F09D6A52@IRVEXCHCCR01.corp.ad.broadcom.com>
In-Reply-To: <3c0b01820805030750k2fc389b0y500914c36069e6cf@mail.gmail.com>
References:  <5D267A3F22FD854F8F48B3D2B523819324F09D65FA@IRVEXCHCCR01.corp.ad.broadcom.com> <3c0b01820805021315i482fe0acg3e9238a2f412770e@mail.gmail.com> <5D267A3F22FD854F8F48B3D2B523819324F09D6896@IRVEXCHCCR01.corp.ad.broadcom.com> <3c0b01820805030750k2fc389b0y500914c36069e6cf@mail.gmail.com>

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> >  Yes, I'm building a debug kernel.  I have the line listed above as
> well
> >  as the following:
> >
> >  options KDB
> >  options DDB
> >  options GDB
> >  options INVARIANTS
> >  options INVARIANT_SUPPORT
> >  options WITNESS
> >  options WITNESS_SKIPSPIN
>
> Dave:
>
> What symbols can you not access exactly and how are you
> installing/setting up debugging?
>
> I just built a RELENG_7 with DDB and I'm able to access bce symbols
> without a problem.  I can examine them and call them.  I'm not using
> options GDB however, only KDB/DDB.
>
> I would:
>
> - Make sure you have the right if_bce.ko/if_bce.ko.symbols files
> generated/installed which contains the debug sections of your ko (from
> the objcopy calls during the build - the binary is stripped with a
> section pointer to the if_bce.ko.symbols file for debugging
> information I believe)
> - If you are using GDB, make sure its pointed to the right source base
> so it can retrieve symbol information correctly
> - If you are using GDB, stub it out and just use DDB to verify that
> your build is sane (it works for me!)
> - If all else fails, you can always build bce statically (just to move
> forward etc.)

- Enable the kernel debugger as described above
- Build the driver in the /usr/src/sys/modules/bce directory with the
  command "make".
- Run the command "nm if_bce.ko | grep dump_stat" in the same directory
  with the kernel module just built.

In my case I only see a symbol for bce_dump_status_block, but there is a
second routine called bce_dump_stats_block.  In my working build there
are 23 functions that start with "bce_dump" but only 8 are displayed with
the command "nm if_bce.ko | grep bce_dump".  Of course, I also get the
symbol not present error when I try to use any of those missing symbols
through a "call" command in the debugger.

Dave





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