From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA9FCC433E0 for ; Tue, 23 Jun 2020 15:25:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E8682064B for ; Tue, 23 Jun 2020 15:25:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733030AbgFWPZf (ORCPT ); Tue, 23 Jun 2020 11:25:35 -0400 Received: from www62.your-server.de ([213.133.104.62]:57924 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732781AbgFWPZd (ORCPT ); Tue, 23 Jun 2020 11:25:33 -0400 Received: from sslproxy05.your-server.de ([78.46.172.2]) by www62.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89_1) (envelope-from ) id 1jnknj-0000qr-6p; Tue, 23 Jun 2020 17:25:31 +0200 Received: from [178.196.57.75] (helo=pc-9.home) by sslproxy05.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jnknL-000TYI-UG; Tue, 23 Jun 2020 17:25:30 +0200 Subject: Re: [PATCH bpf-next 1/3] bpf: introduce helper bpf_get_task_stack_trace() To: Song Liu , bpf@vger.kernel.org, netdev@vger.kernel.org Cc: ast@kernel.org, kernel-team@fb.com, john.fastabend@gmail.com, kpsingh@chromium.org References: <20200623070802.2310018-1-songliubraving@fb.com> <20200623070802.2310018-2-songliubraving@fb.com> From: Daniel Borkmann Message-ID: Date: Tue, 23 Jun 2020 17:22:36 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20200623070802.2310018-2-songliubraving@fb.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.102.3/25852/Tue Jun 23 15:09:58 2020) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 6/23/20 9:08 AM, Song Liu wrote: > This helper can be used with bpf_iter__task to dump all /proc/*/stack to > a seq_file. > > Signed-off-by: Song Liu > --- > include/uapi/linux/bpf.h | 10 +++++++++- > kernel/trace/bpf_trace.c | 21 +++++++++++++++++++++ > scripts/bpf_helpers_doc.py | 2 ++ > tools/include/uapi/linux/bpf.h | 10 +++++++++- > 4 files changed, 41 insertions(+), 2 deletions(-) > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > index 19684813faaed..a30416b822fe3 100644 > --- a/include/uapi/linux/bpf.h > +++ b/include/uapi/linux/bpf.h > @@ -3252,6 +3252,13 @@ union bpf_attr { > * case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level > * is returned or the error code -EACCES in case the skb is not > * subject to CHECKSUM_UNNECESSARY. > + * > + * int bpf_get_task_stack_trace(struct task_struct *task, void *entries, u32 size) > + * Description > + * Save a task stack trace into array *entries*. This is a wrapper > + * over stack_trace_save_tsk(). > + * Return > + * Number of trace entries stored. > */ > #define __BPF_FUNC_MAPPER(FN) \ > FN(unspec), \ > @@ -3389,7 +3396,8 @@ union bpf_attr { > FN(ringbuf_submit), \ > FN(ringbuf_discard), \ > FN(ringbuf_query), \ > - FN(csum_level), > + FN(csum_level), \ > + FN(get_task_stack_trace), > > /* integer value in 'imm' field of BPF_CALL instruction selects which helper > * function eBPF program intends to call > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index e729c9e587a07..2c13bcb5c2bce 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -1488,6 +1488,23 @@ static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = { > .arg4_type = ARG_ANYTHING, > }; > > +BPF_CALL_3(bpf_get_task_stack_trace, struct task_struct *, task, > + void *, entries, u32, size) > +{ > + return stack_trace_save_tsk(task, (unsigned long *)entries, size, 0); nit: cast not needed. > +} > + > +static int bpf_get_task_stack_trace_btf_ids[5]; > +static const struct bpf_func_proto bpf_get_task_stack_trace_proto = { > + .func = bpf_get_task_stack_trace, > + .gpl_only = true, > + .ret_type = RET_INTEGER, > + .arg1_type = ARG_PTR_TO_BTF_ID, > + .arg2_type = ARG_PTR_TO_MEM, > + .arg3_type = ARG_CONST_SIZE_OR_ZERO, Is there a use-case to pass in entries == NULL + size == 0? > + .btf_id = bpf_get_task_stack_trace_btf_ids, > +}; > +