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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 B939FC433E2 for ; Wed, 17 Jun 2020 00:37:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7E27F20810 for ; Wed, 17 Jun 2020 00:37:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="n3JyTVpY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7E27F20810 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0A8CB6B0006; Tue, 16 Jun 2020 20:37:27 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 059B96B0007; Tue, 16 Jun 2020 20:37:27 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E8B6E6B0008; Tue, 16 Jun 2020 20:37:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0006.hostedemail.com [216.40.44.6]) by kanga.kvack.org (Postfix) with ESMTP id CD87E6B0006 for ; Tue, 16 Jun 2020 20:37:26 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 74002180AD804 for ; Wed, 17 Jun 2020 00:37:26 +0000 (UTC) X-FDA: 76936840092.05.walk54_060c9e526e03 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin05.hostedemail.com (Postfix) with ESMTP id 5447818018701 for ; Wed, 17 Jun 2020 00:37:26 +0000 (UTC) X-HE-Tag: walk54_060c9e526e03 X-Filterd-Recvd-Size: 4413 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Wed, 17 Jun 2020 00:37:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:To:From:Date:Sender:Reply-To:Cc: Content-Transfer-Encoding:Content-ID:Content-Description; bh=wFQoXTSBvbEH49Ty46ov9C8/Nsm6g8zmno6k8zfkw2E=; b=n3JyTVpYYWBeG3//7Dbz6/D0OV GzgCh3WX+b3KjXRf4Xu6V0kdWmcuZlo2UQDkR2srryX8xaDqqXUoKDJBqLY7z9Bq/HRtzigf/uuiY Sd9jJpet2hC7DsxpwLEdZSe4WrbCxE6M7EuV4BE8Ch3Qujx54e7p1KIWEuHwoa8nTUBRG0qgKm3X8 u7bLbT0NrHrYEwM3LMHCZKB4a00yRbRrAuqtH54MqoUTLvEdaMZTkNth3X48Dr08NSer2XbXsH4Cc 9E/jX0kKqgw0X02KSRbK/oP/jsZWfFKLiCNdwF4MOhsJnOh7KhHW+wqMLwNoSKm5xDEvSkWRRH8mP +9pgK1yg==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jlM4l-0006AH-5o; Wed, 17 Jun 2020 00:37:11 +0000 Date: Tue, 16 Jun 2020 17:37:11 -0700 From: Matthew Wilcox To: dsterba@suse.cz, Joe Perches , Waiman Long , Andrew Morton , David Howells , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , Linus Torvalds , David Rientjes , Michal Hocko , Johannes Weiner , Dan Carpenter , "Jason A . Donenfeld" , linux-mm@kvack.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, linux-pm@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-amlogic@lists.infradead.org, linux-mediatek@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-ppp@vger.kernel.org, wireguard@lists.zx2c4.com, linux-wireless@vger.kernel.org, devel@driverdev.osuosl.org, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-fscrypt@vger.kernel.org, ecryptfs@vger.kernel.org, kasan-dev@googlegroups.com, linux-bluetooth@vger.kernel.org, linux-wpan@vger.kernel.org, linux-sctp@vger.kernel.org, linux-nfs@vger.kernel.org, tipc-discussion@lists.sourceforge.net, linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org Subject: Re: [PATCH v4 0/3] mm, treewide: Rename kzfree() to kfree_sensitive() Message-ID: <20200617003711.GD8681@bombadil.infradead.org> References: <20200616015718.7812-1-longman@redhat.com> <20200616230130.GJ27795@twin.jikos.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200616230130.GJ27795@twin.jikos.cz> X-Rspamd-Queue-Id: 5447818018701 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 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 Wed, Jun 17, 2020 at 01:01:30AM +0200, David Sterba wrote: > On Tue, Jun 16, 2020 at 11:53:50AM -0700, Joe Perches wrote: > > On Mon, 2020-06-15 at 21:57 -0400, Waiman Long wrote: > > > v4: > > > - Break out the memzero_explicit() change as suggested by Dan Carpenter > > > so that it can be backported to stable. > > > - Drop the "crypto: Remove unnecessary memzero_explicit()" patch for > > > now as there can be a bit more discussion on what is best. It will be > > > introduced as a separate patch later on after this one is merged. > > > > To this larger audience and last week without reply: > > https://lore.kernel.org/lkml/573b3fbd5927c643920e1364230c296b23e7584d.camel@perches.com/ > > > > Are there _any_ fastpath uses of kfree or vfree? > > I'd consider kfree performance critical for cases where it is called > under locks. If possible the kfree is moved outside of the critical > section, but we have rbtrees or lists that get deleted under locks and > restructuring the code to do eg. splice and free it outside of the lock > is not always possible. Not just performance critical, but correctness critical. Since kvfree() may allocate from the vmalloc allocator, I really think that kvfree() should assert that it's !in_atomic(). Otherwise we can get into trouble if we end up calling vfree() and have to take the mutex.