From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6BB18C433E0 for ; Mon, 29 Jun 2020 19:22:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 40722206F1 for ; Mon, 29 Jun 2020 19:22:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730956AbgF2TWS (ORCPT ); Mon, 29 Jun 2020 15:22:18 -0400 Received: from smtprelay0189.hostedemail.com ([216.40.44.189]:42508 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732234AbgF2TVi (ORCPT ); Mon, 29 Jun 2020 15:21:38 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay02.hostedemail.com (Postfix) with ESMTP id 56100513; Mon, 29 Jun 2020 19:21:37 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: toes32_4b0cc6e26e71 X-Filterd-Recvd-Size: 2396 Received: from XPS-9350.home (unknown [47.151.133.149]) (Authenticated sender: joe@perches.com) by omf08.hostedemail.com (Postfix) with ESMTPA; Mon, 29 Jun 2020 19:21:35 +0000 (UTC) Message-ID: <644c67ae316bde28669f660aa5aade274d19a2d0.camel@perches.com> Subject: Re: [PATCH] mm: util: update the kerneldoc for kstrdup_const() From: Joe Perches To: David Hildenbrand , Bartosz Golaszewski , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Bartosz Golaszewski Date: Mon, 29 Jun 2020 12:21:34 -0700 In-Reply-To: <7f1439be-75c4-3a07-ab7b-f4505bf30c48@redhat.com> References: <20200628152500.17916-1-brgl@bgdev.pl> <693db5a878ac09994e2a27c64cb14c0e552f3f50.camel@perches.com> <7f1439be-75c4-3a07-ab7b-f4505bf30c48@redhat.com> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.36.2-0ubuntu1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2020-06-29 at 12:54 +0200, David Hildenbrand wrote: > On 28.06.20 19:37, Joe Perches wrote: > > On Sun, 2020-06-28 at 17:25 +0200, Bartosz Golaszewski wrote: > > > From: Bartosz Golaszewski > > > > > > Memory allocated with kstrdup_const() must not be passed to regular > > > krealloc() as it is not aware of the possibility of the chunk residing > > > in .rodata. Since there are no potential users of krealloc_const() > > > at the moment, let's just update the doc to make it explicit. > > > > Another option would be to return NULL if it's > > used from krealloc with a pointer into rodata [] > > diff --git a/mm/slab_common.c b/mm/slab_common.c [] > > @@ -1683,6 +1683,9 @@ static __always_inline void *__do_krealloc(const void *p, size_t new_size, > > * @new_size: how many bytes of memory are required. > > * @flags: the type of memory to allocate. > > * > > + * If the object pointed to is in rodata (likely from kstrdup_const) > > + * %NULL is returned. > > + * [] > Won't we have similar issues if somebody would do a kfree() instead of a > kfree_const()? So I think the original patch makes sense. Which is why I also suggested making kfree work for more types of memory freeing earlier this month. https://lore.kernel.org/lkml/573b3fbd5927c643920e1364230c296b23e7584d.camel@perches.com/