From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756373AbbJVFcM (ORCPT ); Thu, 22 Oct 2015 01:32:12 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:7932 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751129AbbJVFcK (ORCPT ); Thu, 22 Oct 2015 01:32:10 -0400 Message-ID: <562874A5.1050307@huawei.com> Date: Thu, 22 Oct 2015 13:31:17 +0800 From: "Wangnan (F)" User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Alexei Starovoitov , "David S. Miller" CC: Ingo Molnar , Peter Zijlstra , He Kuang , Kaixu Xia , "Daniel Borkmann" , , Subject: Re: [PATCH v2 net-next] bpf: fix bpf_perf_event_read() helper References: <1445468283-4592-1-git-send-email-ast@kernel.org> In-Reply-To: <1445468283-4592-1-git-send-email-ast@kernel.org> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.111.66.109] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/10/22 6:58, Alexei Starovoitov wrote: > Fix safety checks for bpf_perf_event_read(): > - only non-inherited events can be added to perf_event_array map > (do this check statically at map insertion time) > - dynamically check that event is local and !pmu->count > Otherwise buggy bpf program can cause kernel splat. > > Fixes: 35578d798400 ("bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter") > Signed-off-by: Alexei Starovoitov > --- > v1->v2: fix compile in case of !CONFIG_PERF_EVENTS > > This patch is on top of > http://patchwork.ozlabs.org/patch/533585/ > to avoid conflicts. > Even in the worst case the crash is not possible. > Only warn_on_once, so imo net-next is ok. > > kernel/bpf/arraymap.c | 9 +++++---- > kernel/events/core.c | 16 ++++++++++------ > 2 files changed, 15 insertions(+), 10 deletions(-) > > diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c > index e3cfe46b074f..75529cc94304 100644 > --- a/kernel/bpf/arraymap.c > +++ b/kernel/bpf/arraymap.c > @@ -294,10 +294,11 @@ static void *perf_event_fd_array_get_ptr(struct bpf_map *map, int fd) > if (IS_ERR(attr)) > return (void *)attr; > > - if (attr->type != PERF_TYPE_RAW && > - !(attr->type == PERF_TYPE_SOFTWARE && > - attr->config == PERF_COUNT_SW_BPF_OUTPUT) && > - attr->type != PERF_TYPE_HARDWARE) { > + if ((attr->type != PERF_TYPE_RAW && > + !(attr->type == PERF_TYPE_SOFTWARE && > + attr->config == PERF_COUNT_SW_BPF_OUTPUT) && > + attr->type != PERF_TYPE_HARDWARE) || > + attr->inherit) { This 'if' statement is so complex. What about using a inline function instead? Thank you.