From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754720AbdBVQcT (ORCPT ); Wed, 22 Feb 2017 11:32:19 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55344 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932960AbdBVQcL (ORCPT ); Wed, 22 Feb 2017 11:32:11 -0500 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <1487691808-11289-4-git-send-email-elena.reshetova@intel.com> References: <1487691808-11289-4-git-send-email-elena.reshetova@intel.com> <1487691808-11289-1-git-send-email-elena.reshetova@intel.com> To: Elena Reshetova Cc: dhowells@redhat.com, linux-kernel@vger.kernel.org, linux-afs@lists.infradead.org, peterz@infradead.org, gregkh@linuxfoundation.org, Hans Liljestrand , Kees Cook , David Windsor Subject: Re: [PATCH 3/4] fs, afs: convert afs_server.usage from atomic_t to refcount_t MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <482.1487781128.1@warthog.procyon.org.uk> Date: Wed, 22 Feb 2017 16:32:08 +0000 Message-ID: <483.1487781128@warthog.procyon.org.uk> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Wed, 22 Feb 2017 16:32:12 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Elena Reshetova wrote: > refcount_t type and corresponding API should be > used instead of atomic_t when the variable is used as > a reference counter. This allows to avoid accidental > refcounter overflows that might lead to use-after-free > situations. Although I don't see an assertion for this (the window is too small), it is possible for a dead server record to get resurrected. Take a look at afs_put_server() and note there's a check around the move to the graveyard. So, please hold this patch also. David