From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752112AbbDUGKg (ORCPT ); Tue, 21 Apr 2015 02:10:36 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:57342 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750767AbbDUGKf (ORCPT ); Tue, 21 Apr 2015 02:10:35 -0400 Date: Mon, 20 Apr 2015 23:10:34 -0700 From: Christoph Hellwig To: Ron Rechenmacher Cc: linux-kernel@vger.kernel.org, Steven Rostedt Subject: Re: [PATCH] tracing: Export key trace event symbols Message-ID: <20150421061034.GA9253@infradead.org> References: <553571C3.1060505@fnal.gov> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <553571C3.1060505@fnal.gov> User-Agent: Mutt/1.5.23 (2014-03-12) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 20, 2015 at 04:38:11PM -0500, Ron Rechenmacher wrote: > If symbols are not exported, modules can no longer register additional > (module specified) tracepoints like they use to be able to (i.e linux-3.15.x). > Somewhere on or about commit de7b2973903c6cc50b31ee5682a69b2219b9919d > (Author: Mathieu Desnoyers > Date: Tue Apr 8 17:26:21 2014 -0400 > tracepoint: Use struct pointer instead of name hash for reg/unreg tracepoints) > modules which attempted to register additional tracing functions would > get "Unknown symbol" errors. For example: "... Unknown symbol > __tracepoint_sched_switch (err 0)" > Symbols can be exported using the kernel's EXPORT_TRACEPOINT_SYMBOL_GPL macro > to allow modules to once again register their own tracing functions (for at > least some key points in the kernel as provided by this patch). Which (in-tree) module fails with this? I don't think anyone should actually register a symbol.