From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Masters Subject: try_module_get and friends Date: Tue, 04 Mar 2008 00:20:58 -0500 Message-ID: <1204608058.11912.3.camel@perihelion> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: linux-rt-users , Ingo Molnar , Thomas Gleixner To: Steven Rostedt Return-path: Received: from dallas.jonmasters.org ([72.29.103.172]:60559 "EHLO dallas.jonmasters.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752208AbYCDFVu (ORCPT ); Tue, 4 Mar 2008 00:21:50 -0500 Sender: linux-rt-users-owner@vger.kernel.org List-ID: Yo, Ok...so I might just be missing something and you guys will set me right if that is indeed the case, but... What's protecting the -RT kernel from assumptions about atomicity of module symbol references? Specifically, the kernel doesn't normally need to protect against inter-module symbol references to EXPORT_SYMBOL(s), however, it requires special protection when a function pointer is being passed around - that's why we use things like try_module_get. But it is assumed that it is ok not to do this in atomic contexts. So, what's protecting the RT kernel from falling over if a CPU frequency governor module is removed at the wrong moment? Jon.