From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aleksa Sarai Subject: [PATCH 0/2] cgroup: pids: fix invalid reference semantics Date: Sun, 23 Aug 2015 23:10:30 +1000 Message-ID: <1440335432-4202-1-git-send-email-cyphar@cyphar.com> References: Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: tj@kernel.org Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Aleksa Sarai I've discovered a bug in the PIDs cgroup. We aren't properly dealing with css references (we grab a reference to a css in ->can_attach() and then drop a reference to a *different* css in ->{cancel_,}attach(). This is a quick patch I wrote which I believe fixes the problem by getting cgroup_migrate() to grab a reference before ->can_attach() and once the attach has failed or succeded. Aleksa Sarai (2): cgroup: get a ref to source csses when migrating cgroup: pids: fix invalid get/put usage kernel/cgroup.c | 21 +++++++++++++++++++-- kernel/cgroup_pids.c | 13 +------------ 2 files changed, 20 insertions(+), 14 deletions(-) -- 2.5.0