From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:58912 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729165AbeIXSmD (ORCPT ); Mon, 24 Sep 2018 14:42:03 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Roman Gushchin , Alexei Starovoitov , Daniel Borkmann , Sasha Levin Subject: [PATCH 4.18 152/235] bpf: fix rcu annotations in compute_effective_progs() Date: Mon, 24 Sep 2018 13:52:18 +0200 Message-Id: <20180924113120.557117770@linuxfoundation.org> In-Reply-To: <20180924113103.999624566@linuxfoundation.org> References: <20180924113103.999624566@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Roman Gushchin [ Upstream commit 3960f4fd6585608e8cc285d9665821985494e147 ] The progs local variable in compute_effective_progs() is marked as __rcu, which is not correct. This is a local pointer, which is initialized by bpf_prog_array_alloc(), which also now returns a generic non-rcu pointer. The real rcu-protected pointer is *array (array is a pointer to an RCU-protected pointer), so the assignment should be performed using rcu_assign_pointer(). Fixes: 324bda9e6c5a ("bpf: multi program support for cgroup+bpf") Signed-off-by: Roman Gushchin Cc: Alexei Starovoitov Cc: Daniel Borkmann Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/cgroup.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -95,7 +95,7 @@ static int compute_effective_progs(struc enum bpf_attach_type type, struct bpf_prog_array __rcu **array) { - struct bpf_prog_array __rcu *progs; + struct bpf_prog_array *progs; struct bpf_prog_list *pl; struct cgroup *p = cgrp; int cnt = 0; @@ -120,13 +120,12 @@ static int compute_effective_progs(struc &p->bpf.progs[type], node) { if (!pl->prog) continue; - rcu_dereference_protected(progs, 1)-> - progs[cnt++] = pl->prog; + progs->progs[cnt++] = pl->prog; } p = cgroup_parent(p); } while (p); - *array = progs; + rcu_assign_pointer(*array, progs); return 0; }