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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 70B50C2BA1B for ; Mon, 6 Apr 2020 16:40:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0ADE721D79 for ; Mon, 6 Apr 2020 16:40:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0ADE721D79 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=perches.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 63A568E0048; Mon, 6 Apr 2020 12:40:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5EA018E000D; Mon, 6 Apr 2020 12:40:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5000E8E0048; Mon, 6 Apr 2020 12:40:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0028.hostedemail.com [216.40.44.28]) by kanga.kvack.org (Postfix) with ESMTP id 33DB68E000D for ; Mon, 6 Apr 2020 12:40:16 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id E32D0801C0F4 for ; Mon, 6 Apr 2020 16:40:15 +0000 (UTC) X-FDA: 76677992790.06.women53_1eec5c4484f38 X-HE-Tag: women53_1eec5c4484f38 X-Filterd-Recvd-Size: 3061 Received: from smtprelay.hostedemail.com (smtprelay0120.hostedemail.com [216.40.44.120]) by imf28.hostedemail.com (Postfix) with ESMTP for ; Mon, 6 Apr 2020 16:40:12 +0000 (UTC) Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay04.hostedemail.com (Postfix) with ESMTP id 1D09D180A814B; Mon, 6 Apr 2020 16:40:12 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: knee59_1e264919b4416 X-Filterd-Recvd-Size: 1926 Received: from XPS-9350.home (unknown [47.151.136.130]) (Authenticated sender: joe@perches.com) by omf10.hostedemail.com (Postfix) with ESMTPA; Mon, 6 Apr 2020 16:40:07 +0000 (UTC) Message-ID: Subject: Re: [PATCH] mm: Add kvfree_sensitive() for freeing sensitive data objects From: Joe Perches To: David Howells Cc: Waiman Long , Andrew Morton , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , linux-mm@kvack.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org, Linus Torvalds Date: Mon, 06 Apr 2020 09:38:08 -0700 In-Reply-To: <334933.1586190389@warthog.procyon.org.uk> References: <20200406023700.1367-1-longman@redhat.com> <319765.1586188840@warthog.procyon.org.uk> <334933.1586190389@warthog.procyon.org.uk> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.34.1-2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, 2020-04-06 at 17:26 +0100, David Howells wrote: > Joe Perches wrote: > > > While I agree with Linus about the __ prefix, > > the z is pretty common and symmetric to all > > the zalloc uses. > > > > And if _sensitive is actually used, it'd be > > good to do a s/kzfree/kfree_sensitive/ one day > > sooner than later. > > How much overhead would it be to always use kvfree_sensitive() and never have > a kfree_sensitive()? I believe the is_vmalloc_addr not particularly expensive as it's just 2 tests. It might make sense to go back to static inline is_vmalloc_addr instead of using EXPORT_SYMBOL