From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aijaz Baig Subject: help needed with EXPORT_SYMBOL Date: Sat, 21 Aug 2010 12:27:14 +0530 Message-ID: <1282373834.4080.79.camel@aijazbaig1-desktop> Reply-To: aijazbaig1@gmail.com Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org To: netfilter-devel@vger.kernel.org Return-path: Received: from mail-px0-f174.google.com ([209.85.212.174]:53174 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751211Ab0HUG5W (ORCPT ); Sat, 21 Aug 2010 02:57:22 -0400 Sender: netfilter-devel-owner@vger.kernel.org List-ID: Hello, Ive been trying to EXPORT a SYMBOL from a netfilter module (actually a hook) to the KERNEL. Various modules seem to export various symbols to the kernel (or so it seems), an example being x_tables which exports a whole lot of functions like xt_register_target and so on and all other netfilter modules which use these functions dont seem to have any problems. So why is it that when my netfilter module is exporting something to the kernel and im tryin to use it from within a core kernel file, the compiler flags a 'undefined reference to' error? I googled and came to the conclusion from the kernelnewbies mailing list that using kallsyms_lookup() seems to be the answer or is it? So, if I do intend to use kallsyms_lookup how do I use it? There aren't so many instances of it being used it seems. Ive seen it being used in dev/core.c like so: symname = kallsyms_lookup((unsigned long)sym, &symsize,&offset,&modname, namebuf); I am basically trying to call a function that MY module EXPORTs inside one of the core linux routines. This would also mean that my netfilter module must be compiled (and linked also maybe?..not so sound with link time stuff) before the address becomes visible so that kallsyms_lookup can find it. So do I really shd be using it and if so, how? Any input is appreciated. Regards, Aijaz Baig.