From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Perches Date: Wed, 17 Jun 2020 23:12:06 +0000 Subject: Re: [PATCH v4 0/3] mm, treewide: Rename kzfree() to kfree_sensitive() Message-Id: <38c5745d14cff75fe264a3bc61d19fd837baf7ad.camel@perches.com> List-Id: References: <20200616015718.7812-1-longman@redhat.com> <17e4fede-bab0-d93c-6964-69decc889d7d@ispras.ru> In-Reply-To: <17e4fede-bab0-d93c-6964-69decc889d7d@ispras.ru> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Denis Efremov , Waiman Long , Andrew Morton , David Howells , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , Linus Torvalds , Matthew Wilcox , David Rientjes Cc: "Jason A . Donenfeld" , Michal Hocko , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-sctp@vger.kernel.org, target-devel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, devel@driverdev.osuosl.org, linux-cifs@vger.kernel.org, linux-scsi@vger.kernel.org, kasan-dev@googlegroups.com, linux-wpan@vger.kernel.org, Dan Carpenter , linux-pm@vger.kernel.org, ecryptfs@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-amlogic@lists.infradead.org, virtualization@lists.linux-foundation.org, linux-nfs@vger.kernel.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, David Sterba , linux-bluetooth@vger.kernel.org, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, tipc-discussion@lists.sourceforge.net, linux-crypto@vger.kernel.org, Johannes Weiner , linux-integrity@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, wireguard@lists.zx2c4.com, linux-ppp@vger.kernel.org On Thu, 2020-06-18 at 00:31 +0300, Denis Efremov wrote: > > On 6/16/20 9:53 PM, 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? > > > > Many patches have been posted recently to fix mispairings > > of specific types of alloc and free functions. > > I've prepared a coccinelle script to highlight these mispairings in a function > a couple of days ago: https://lkml.org/lkml/2020/6/5/953 > I've listed all the fixes in the commit message. > > Not so many mispairings actually, and most of them are harmless like: > kmalloc(E) -> kvfree(E) > > However, coccinelle script can't detect cross-functions mispairings, i.e. > allocation in one function, free in another funtion. Hey Denis, thanks for those patches. If possible, it's probably better to not require these pairings and use a single standard kfree/free function. Given the existing ifs in kfree in slab/slob/slub, it seems likely that adding a few more wouldn't have much impact.