Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965870AbbLQLje (ORCPT ); Thu, 17 Dec 2015 06:39:34 -0500 Received: from mx2.suse.de ([195.135.220.15]:40981 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751349AbbLQLjb (ORCPT ); Thu, 17 Dec 2015 06:39:31 -0500 Date: Thu, 17 Dec 2015 12:39:28 +0100 (CET) From: Miroslav Benes To: Jessica Yu cc: Rusty Russell , Josh Poimboeuf , Seth Jennings , Jiri Kosina , Vojtech Pavlik , Jonathan Corbet , linux-api@vger.kernel.org, live-patching@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: module: s390: keep mod_arch_specific for livepatch modules In-Reply-To: <20151216234828.GB29092@packer-debian-8-amd64.digitalocean.com> Message-ID: References: <1448943679-3412-1-git-send-email-jeyu@redhat.com> <1448943679-3412-4-git-send-email-jeyu@redhat.com> <20151216234828.GB29092@packer-debian-8-amd64.digitalocean.com> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2678 Lines: 67 On Wed, 16 Dec 2015, Jessica Yu wrote: > +++ Miroslav Benes [16/12/15 13:02 +0100]: > > On Mon, 30 Nov 2015, Jessica Yu wrote: > > > > > Livepatch needs to utilize the symbol information contained in the > > > mod_arch_specific struct in order to be able to call the s390 > > > apply_relocate_add() function to apply relocations. Remove the redundant > > > vfree() in module_finalize() since module_arch_freeing_init() (which also > > > frees > > > said structures) is called in do_init_module(). Keep a reference to > > > syminfo if > > > the module is a livepatch module and free the structures in > > > module_arch_cleanup(). If the module isn't a livepatch module, we free the > > > structures in module_arch_freeing_init() as usual. > > > > > > Signed-off-by: Jessica Yu > > > --- > > > arch/s390/kernel/module.c | 13 +++++++++++-- > > > 1 file changed, 11 insertions(+), 2 deletions(-) > > > > > > diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c > > > index 0c1a679..17a1979 100644 > > > --- a/arch/s390/kernel/module.c > > > +++ b/arch/s390/kernel/module.c > > > @@ -51,6 +51,9 @@ void *module_alloc(unsigned long size) > > > > > > void module_arch_freeing_init(struct module *mod) > > > { > > > + if (mod->klp) > > > + return; > > > + > > > vfree(mod->arch.syminfo); > > > mod->arch.syminfo = NULL; > > > } > > > > Hm, this is problematic. module_arch_freeing_init() is called from > > module_deallocate() and this is called in the error path in load_module(). > > So if there was an error during load_module() of livepatch module which > > led to free_modinfo label or behind mod->arch.syminfo would not be freed > > at all. module_arch_cleanup() is called earlier under > > free_arch_cleanup. > > Gah. Good catch. How about we add an additional check to see if > mod->state is MODULE_STATE_LIVE? If so, we can return. This means > we're coming from do_init_module(). If module_arch_freeing_init() was > called and the module was in a state other than MODULE_STATE_LIVE > (UNFORMED, GOING, COMING), we know we need to free. Think that would > work? It would I think. module_arch_freeing_init is called thrice. 1. in free_module(). The module is in UNFORMED state so everything is fine. 2. in module_deallocate(). The module is not LIVE yet here so ok as well. 3. in do_init_module() and the module is LIVE there. So yes, you are right, that should work. Miroslav -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/