From patchwork Tue Aug 18 16:24:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 1347145 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.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=bpf-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=i1S3IDsT; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4BWGTL3j87z9sTH for ; Wed, 19 Aug 2020 02:24:38 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726739AbgHRQYd (ORCPT ); Tue, 18 Aug 2020 12:24:33 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:37952 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726713AbgHRQYU (ORCPT ); Tue, 18 Aug 2020 12:24:20 -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 07IGNSMR011420 for ; Tue, 18 Aug 2020 09:24:19 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=uivpPlGrhYZz9V9w7N8wqLijUdhA/Lsu7oxgPtK9cK0=; b=i1S3IDsT1J/YvpfgmXO+kaXMd1qeD7Zg8CG3g7FAnNEhPMhQZArcKpqCc7c/linxzK9R K8B+3u2h6TdZ3Q3UIviD3pPYL9dF2uHl2uquBqaQF9KJtIOrgtIEUNsnxAse26c/NlD4 VqAHx67G9BeLtJ0A8rkJSNlL9kQlG0CaJ8Y= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 3304p7unr9-8 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 18 Aug 2020 09:24:19 -0700 Received: from intmgw005.03.ash8.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; Tue, 18 Aug 2020 09:24:13 -0700 Received: by devbig003.ftw2.facebook.com (Postfix, from userid 128203) id A3EAB37036A5; Tue, 18 Aug 2020 09:24:09 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Yonghong Song Smtp-Origin-Hostname: devbig003.ftw2.facebook.com To: , CC: Alexei Starovoitov , Daniel Borkmann , , Rik van Riel Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH bpf 2/2] bpf: avoid visit same object multiple times Date: Tue, 18 Aug 2020 09:24:09 -0700 Message-ID: <20200818162409.837005-1-yhs@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200818162408.836759-1-yhs@fb.com> References: <20200818162408.836759-1-yhs@fb.com> 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=2020-08-18_11:2020-08-18,2020-08-18 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 suspectscore=8 adultscore=0 priorityscore=1501 malwarescore=0 mlxlogscore=787 clxscore=1015 spamscore=0 bulkscore=0 mlxscore=0 lowpriorityscore=0 phishscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2008180116 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Currently when traversing all tasks, the next tid is always increased by one. This may result in visiting the same task multiple times in a pid namespace. This patch fixed the issue by seting the next tid as pid_nr_ns(pid, ns) + 1, similar to funciton next_tgid(). Cc: Rik van Riel Signed-off-by: Yonghong Song --- kernel/bpf/task_iter.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c index 885b14cab2c0..d6e1a141ea5c 100644 --- a/kernel/bpf/task_iter.c +++ b/kernel/bpf/task_iter.c @@ -31,8 +31,9 @@ static struct task_struct *task_seq_get_next(struct pid_namespace *ns, rcu_read_lock(); retry: - pid = idr_get_next(&ns->idr, tid); + pid = find_ge_pid(*tid, ns); if (pid) { + *tid = pid_nr_ns(pid, ns); task = get_pid_task(pid, PIDTYPE_PID); if (!task) { ++*tid;