Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752318AbbKKORR (ORCPT ); Wed, 11 Nov 2015 09:17:17 -0500 Received: from mx2.suse.de ([195.135.220.15]:34642 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750862AbbKKORQ (ORCPT ); Wed, 11 Nov 2015 09:17:16 -0500 Date: Wed, 11 Nov 2015 15:17:15 +0100 (CET) From: Miroslav Benes To: Jessica Yu cc: Rusty Russell , Josh Poimboeuf , Seth Jennings , Jiri Kosina , Vojtech Pavlik , linux-api@vger.kernel.org, live-patching@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 2/5] module: save load_info for livepatch modules In-Reply-To: <1447130755-17383-3-git-send-email-jeyu@redhat.com> Message-ID: References: <1447130755-17383-1-git-send-email-jeyu@redhat.com> <1447130755-17383-3-git-send-email-jeyu@redhat.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: 2619 Lines: 79 On Mon, 9 Nov 2015, Jessica Yu wrote: > diff --git a/include/linux/module.h b/include/linux/module.h > index 3a19c79..c8680b1 100644 > --- a/include/linux/module.h > +++ b/include/linux/module.h [...] > +#ifdef CONFIG_LIVEPATCH > +extern void klp_prepare_patch_module(struct module *mod, > + struct load_info *info); > +extern int > +apply_relocate_add(Elf64_Shdr *sechdrs, const char *strtab, > + unsigned int symindex, unsigned int relsec, > + struct module *me); > +#endif > + > #else /* !CONFIG_MODULES... */ apply_relocate_add() is already in include/linux/moduleloader.h (guarded by CONFIG_MODULES_USE_ELF_RELA), so maybe we can just include that where we need it. As for the klp_prepare_patch_module() wouldn't it be better to have it in our livepatch.h and include that in kernel/module.c? > /* Given an address, look for it in the exception tables. */ > diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c > index 6e53441..087a8c7 100644 > --- a/kernel/livepatch/core.c > +++ b/kernel/livepatch/core.c > @@ -1001,6 +1001,23 @@ static struct notifier_block klp_module_nb = { > .priority = INT_MIN+1, /* called late but before ftrace notifier */ > }; > > +/* > + * Save necessary information from info in order to be able to > + * patch modules that might be loaded later > + */ > +void klp_prepare_patch_module(struct module *mod, struct load_info *info) > +{ > + Elf_Shdr *symsect; > + > + symsect = info->sechdrs + info->index.sym; > + /* update sh_addr to point to symtab */ > + symsect->sh_addr = (unsigned long)info->hdr + symsect->sh_offset; > + > + mod->info = kzalloc(sizeof(*info), GFP_KERNEL); > + memcpy(mod->info, info, sizeof(*info)); > + > +} What about arch-specific 'struct mod_arch_specific'? We need to preserve it somewhere as well for s390x and other non-x86 architectures. > +#ifdef CONFIG_LIVEPATCH > + /* > + * Save sechdrs, indices, and other data from info > + * in order to patch to-be-loaded modules. > + * Do not call free_copy() for livepatch modules. > + */ > + if (get_modinfo((struct load_info *)info, "livepatch")) > + klp_prepare_patch_module(mod, info); > + else > + free_copy(info); > +#else > /* Get rid of temporary copy. */ > free_copy(info); > +#endif Maybe I am missing something but isn't it necessary to call vfree() on info somewhere in the end? Regards, 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/