From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jason A. Donenfeld" Date: Tue, 16 Jun 2020 19:46:46 +0000 Subject: Re: [PATCH v4 0/3] mm, treewide: Rename kzfree() to kfree_sensitive() Message-Id: List-Id: References: <20200616015718.7812-1-longman@redhat.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Joe Perches Cc: Michal Hocko , linux-btrfs@vger.kernel.org, Jarkko Sakkinen , David Sterba , David Howells , Linux-MM , linux-sctp@vger.kernel.org, keyrings@vger.kernel.org, kasan-dev@googlegroups.com, linux-stm32@st-md-mailman.stormreply.com, devel@driverdev.osuosl.org, linux-cifs@vger.kernel.org, linux-scsi@vger.kernel.org, James Morris , Matthew Wilcox , linux-wpan@vger.kernel.org, David Rientjes , Waiman Long , Dan Carpenter , Steffen Klassert , 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-integrity@vger.kernel.org, linux-nfs@vger.kernel.org, Linus Torvalds , linux-wireless , LKML , David Miller , linux-bluetooth@vger.kernel.org, linux-security-module , target-devel@vger.kernel.org, tipc-discussion@lists.sourceforge.net, Linux Crypto Mailing List , Johannes Weiner , Andrew Morton , linuxppc-dev@lists.ozlabs.org, Netdev , WireGuard mailing list , linux-ppp@vger.kernel.org On Tue, Jun 16, 2020 at 12:54 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? The networking stack has various places where there will be a quick kmalloc followed by a kfree for an incoming or outgoing packet. One place that comes to mind would be esp_alloc_tmp, which does a quick allocation of some temporary kmalloc memory, processes some packet things inside of that, and then frees it, sometimes in the same function, and sometimes later in an async callback. I don't know how "fastpath" you consider this, but usually packet processing is something people want to do with minimal overhead, considering how fast NICs are these days.