From patchwork Sat Jun 27 00:26:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 217007 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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=no 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 21173C433E0 for ; Sat, 27 Jun 2020 00:26:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E921E2081A for ; Sat, 27 Jun 2020 00:26:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="dj5nFQ0s" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726563AbgF0A0s (ORCPT ); Fri, 26 Jun 2020 20:26:48 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:35670 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726056AbgF0A0W (ORCPT ); Fri, 26 Jun 2020 20:26:22 -0400 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 05R0BZdq012712 for ; Fri, 26 Jun 2020 17:26:22 -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=GM6A8UjAF0fo4iVW+BpkuaPZ8qEq48fS4fEZOdfNKXk=; b=dj5nFQ0sYN0px8jy4hratYAGTN6L8Fd/FIVQ9J/TiJJcdCZLQDxruZdCOYgGktwqzgNh 90sDK3MsGCGjA70GT86M+2m8jI6wrFWtsD8oe0W9N5R0sG7xMyvv6xFGIJ2ASqjHHq0f 3fYeAfZqDweRbfrQLq9HnWIyWkGGXIrQwr0= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 31ux0w86qn-5 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 26 Jun 2020 17:26:22 -0700 Received: from intmgw004.08.frc2.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Fri, 26 Jun 2020 17:26:19 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id B00FE62E4DEC; Fri, 26 Jun 2020 17:26:15 -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 v3 bpf-next 0/4] bpf: introduce bpf_get_task_stack() Date: Fri, 26 Jun 2020 17:26:04 -0700 Message-ID: <20200627002609.3222870-1-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=2.50.10434:6.0.216, 18.0.687 definitions=2020-06-26_12:2020-06-26,2020-06-26 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 bulkscore=0 cotscore=-2147483648 mlxscore=0 suspectscore=0 adultscore=0 phishscore=0 clxscore=1015 spamscore=0 mlxlogscore=999 lowpriorityscore=0 impostorscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006270000 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 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 | 75 ++++++++++++++++++- 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 | 53 +++++++++++++ 11 files changed, 236 insertions(+), 15 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c --- 2.24.1