From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yonghong Song Subject: [PATCH net 1/2] bpf: set maximum number of attached progs to 64 for a single perf tp Date: Thu, 30 Nov 2017 13:47:54 -0800 Message-ID: <20171130214755.3022117-1-yhs@fb.com> Mime-Version: 1.0 Content-Type: text/plain Cc: To: , , Return-path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:36346 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751256AbdK3Vr5 (ORCPT ); Thu, 30 Nov 2017 16:47:57 -0500 Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id vAULkFNP026157 for ; Thu, 30 Nov 2017 13:47:57 -0800 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2ejqqu8jat-2 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Thu, 30 Nov 2017 13:47:56 -0800 Sender: netdev-owner@vger.kernel.org List-ID: cgropu+bpf prog array has a maximum number of 64 programs. Let us apply the same limit here. Signed-off-by: Yonghong Song --- kernel/bpf/core.c | 3 ++- kernel/trace/bpf_trace.c | 8 ++++++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index b9f8686..86b50aa 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1447,7 +1447,8 @@ int bpf_prog_array_length(struct bpf_prog_array __rcu *progs) rcu_read_lock(); prog = rcu_dereference(progs)->progs; for (; *prog; prog++) - cnt++; + if (*prog != &dummy_bpf_prog.prog) + cnt++; rcu_read_unlock(); return cnt; } diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 27d1f4f..0ce99c3 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -759,6 +759,8 @@ const struct bpf_prog_ops perf_event_prog_ops = { static DEFINE_MUTEX(bpf_event_mutex); +#define BPF_TRACE_MAX_PROGS 64 + int perf_event_attach_bpf_prog(struct perf_event *event, struct bpf_prog *prog) { @@ -772,6 +774,12 @@ int perf_event_attach_bpf_prog(struct perf_event *event, goto unlock; old_array = event->tp_event->prog_array; + if (old_array && + bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) { + ret = -E2BIG; + goto unlock; + } + ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); if (ret < 0) goto unlock; -- 2.9.5