From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758909Ab0I0IWk (ORCPT ); Mon, 27 Sep 2010 04:22:40 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:59659 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755911Ab0I0IWj convert rfc822-to-8bit (ORCPT ); Mon, 27 Sep 2010 04:22:39 -0400 Date: Mon, 27 Sep 2010 16:22:47 +0800 From: Hu Tao To: =?utf-8?Q?Am=C3=A9rico?= Wang Cc: lkml , Rusty Russell , Tejun Heo , Andrew Morton Subject: Re: [PATCH] Update num_symtab, symtab and strtab right after setup of core_num_syms, core_symtab and core_strtab. Message-ID: <20100927082247.GA2463@localhost.localdomain> References: <20100927073028.GA1040@localhost.localdomain> <20100927080954.GC5785@cr0.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20100927080954.GC5785@cr0.nay.redhat.com> User-Agent: Mutt/1.5.20 (2009-12-10) Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 27, 2010 at 04:09:54PM +0800, Américo Wang wrote: > On Mon, Sep 27, 2010 at 03:30:28PM +0800, Hu Tao wrote: > >Signed-off-by: Hu Tao > > > Changelog is empty. > What bug did you observe? symtab and strtab will point to vfreed memory after free_copy(&info) near end of load_module(). > > >--- > > kernel/module.c | 9 ++++----- > > 1 files changed, 4 insertions(+), 5 deletions(-) > > > >diff --git a/kernel/module.c b/kernel/module.c > >index d0b5f8d..d5dc98b 100644 > >--- a/kernel/module.c > >+++ b/kernel/module.c > >@@ -2029,6 +2029,10 @@ static void add_kallsyms(struct module *mod, const struct load_info *info) > > for (*s = 0, i = 1; i < info->sechdrs[info->index.str].sh_size; ++i) > > if (test_bit(i, info->strmap)) > > *++s = mod->strtab[i]; > >+ > >+ mod->num_symtab = mod->core_num_syms; > >+ mod->symtab = mod->core_symtab; > >+ mod->strtab = mod->core_strtab; > > } > > #else > > static inline void layout_symtab(struct module *mod, struct load_info *info) > >@@ -2738,11 +2742,6 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, > > /* Drop initial reference. */ > > module_put(mod); > > trim_init_extable(mod); > >-#ifdef CONFIG_KALLSYMS > >- mod->num_symtab = mod->core_num_syms; > >- mod->symtab = mod->core_symtab; > >- mod->strtab = mod->core_strtab; > >-#endif > > module_free(mod, mod->module_init); > > mod->module_init = NULL; > > mod->init_size = 0; > > > This patch is not correct, symbols that are not core symbols will be > dropped right after this piece of code. So NACK. There is the reason why we should update num_symtab, symtab and strtab before non-core-symbols are dropped.