From patchwork Tue Jun 30 06:28:42 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 1319572 Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.a=rsa-sha256 header.s=facebook header.b=fY7q+dyr; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49wvZj12Wjz9sQx for ; Tue, 30 Jun 2020 16:29:01 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730369AbgF3G25 (ORCPT ); Tue, 30 Jun 2020 02:28:57 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:13146 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730096AbgF3G24 (ORCPT ); Tue, 30 Jun 2020 02:28:56 -0400 Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 05U6StX8018789 for ; Mon, 29 Jun 2020 23:28:56 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding : content-type; s=facebook; bh=ATAIZRyF5LF5Ymt6TlkUCcEq7zggg+i+C8LAuUJjSjU=; b=fY7q+dyrU9O3KHHf1c7Dkel+wQFs1sj9DvNCBMuaxaShpdAzRCEKa7QAoVLxxRwtOEnJ e8dDtpYsgQn9xmnvbe1HuUVONKA0vlnYw6ygCU7LEXRGma+K8i8CIKan7U1LD9rKPzsY 4S/N6Qfows/1fJs8wnBKfw8X78I1W5dnPPQ= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 31xp398gmb-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 29 Jun 2020 23:28:55 -0700 Received: from intmgw003.08.frc2.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:21d::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Mon, 29 Jun 2020 23:28:55 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 593F062E51C7; Mon, 29 Jun 2020 23:28:50 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Song Liu Smtp-Origin-Hostname: devbig006.ftw2.facebook.com To: , , CC: , , , , , , Song Liu Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH v5 bpf-next 0/4] bpf: introduce bpf_get_task_stack() Date: Mon, 29 Jun 2020 23:28:42 -0700 Message-ID: <20200630062846.664389-1-songliubraving@fb.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-06-30_01:2020-06-30,2020-06-29 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 adultscore=0 impostorscore=0 phishscore=0 cotscore=-2147483648 malwarescore=0 lowpriorityscore=0 mlxscore=0 suspectscore=0 clxscore=1015 priorityscore=1501 bulkscore=0 spamscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006300048 X-FB-Internal: deliver Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This set introduces a new helper bpf_get_task_stack(). The primary use case is to dump all /proc/*/stack to seq_file via bpf_iter__task. A few different approaches have been explored and compared: 1. A simple wrapper around stack_trace_save_tsk(), as v1 [1]. This approach introduces new syntax, which is different to existing helper bpf_get_stack(). Therefore, this is not ideal. 2. Extend get_perf_callchain() to support "task" as argument. This approach reuses most of bpf_get_stack(). However, extending get_perf_callchain() requires non-trivial changes to architecture specific code. Which is error prone. 3. Current (v2) approach, leverages most of existing bpf_get_stack(), and uses stack_trace_save_tsk() to handle architecture specific logic. [1] https://lore.kernel.org/netdev/20200623070802.2310018-1-songliubraving@fb.com/ Changes v4 => v5: 1. Rebase and work around git-am issue. (Alexei) 2. Update commit log for 4/4. (Yonghong) Changes v3 => v4: 1. Simplify the selftests with bpf_iter.h. (Yonghong) 2. Add example output to commit log of 4/4. (Yonghong) Changes v2 => v3: 1. Rebase on top of bpf-next. (Yonghong) 2. Sanitize get_callchain_entry(). (Peter) 3. Use has_callchain_buf for bpf_get_task_stack. (Andrii) 4. Other small clean up. (Yonghong, Andrii). Changes v1 => v2: 1. Reuse most of bpf_get_stack() logic. (Andrii) 2. Fix unsigned long vs. u64 mismatch for 32-bit systems. (Yonghong) 3. Add %pB support in bpf_trace_printk(). (Daniel) 4. Fix buffer size to bytes. Song Liu (4): perf: expose get/put_callchain_entry() bpf: introduce helper bpf_get_task_stack() bpf: allow %pB in bpf_seq_printf() and bpf_trace_printk() selftests/bpf: add bpf_iter test with bpf_get_task_stack() include/linux/bpf.h | 1 + include/linux/perf_event.h | 2 + include/uapi/linux/bpf.h | 36 ++++++++- kernel/bpf/stackmap.c | 77 ++++++++++++++++++- kernel/bpf/verifier.c | 4 +- kernel/events/callchain.c | 13 ++-- kernel/trace/bpf_trace.c | 12 ++- scripts/bpf_helpers_doc.py | 2 + tools/include/uapi/linux/bpf.h | 36 ++++++++- .../selftests/bpf/prog_tests/bpf_iter.c | 17 ++++ .../selftests/bpf/progs/bpf_iter_task_stack.c | 37 +++++++++ 11 files changed, 221 insertions(+), 16 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c --- 2.24.1