{"id":1238819,"url":"http://patchwork.ozlabs.org/api/patches/1238819/?format=json","web_url":"http://patchwork.ozlabs.org/project/netdev/patch/20200216193005.144157-11-jolsa@kernel.org/","project":{"id":7,"url":"http://patchwork.ozlabs.org/api/projects/7/?format=json","name":"Linux network development","link_name":"netdev","list_id":"netdev.vger.kernel.org","list_email":"netdev@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20200216193005.144157-11-jolsa@kernel.org>","list_archive_url":null,"date":"2020-02-16T19:29:57","name":"[10/18] bpf: Re-initialize lnode in bpf_ksym_del","commit_ref":null,"pull_url":null,"state":"changes-requested","archived":false,"hash":"72c72f20b088ffed4766117a1a56d5d90a68f8b0","submitter":{"id":73687,"url":"http://patchwork.ozlabs.org/api/people/73687/?format=json","name":"Jiri Olsa","email":"jolsa@kernel.org"},"delegate":{"id":77147,"url":"http://patchwork.ozlabs.org/api/users/77147/?format=json","username":"bpf","first_name":"BPF","last_name":"Maintainers","email":"bpf@iogearbox.net"},"mbox":"http://patchwork.ozlabs.org/project/netdev/patch/20200216193005.144157-11-jolsa@kernel.org/mbox/","series":[{"id":158829,"url":"http://patchwork.ozlabs.org/api/series/158829/?format=json","web_url":"http://patchwork.ozlabs.org/project/netdev/list/?series=158829","date":"2020-02-16T19:29:47","name":"bpf: Add trampoline and dispatcher to /proc/kallsyms","version":1,"mbox":"http://patchwork.ozlabs.org/series/158829/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/1238819/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/1238819/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming-bpf@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming-bpf@bilbo.ozlabs.org","Authentication-Results":["ozlabs.org; spf=none (no SPF record)\n\tsmtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67;\n\thelo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org;\n\treceiver=)","ozlabs.org;\n\tdmarc=fail (p=none dis=none) header.from=kernel.org"],"Received":["from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 48LHKd6Vwlz9sP7\n\tfor ;\n\tMon, 17 Feb 2020 06:31:17 +1100 (AEDT)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1727936AbgBPTbR convert rfc822-to-8bit (ORCPT\n\t);\n\tSun, 16 Feb 2020 14:31:17 -0500","from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:33444 \"EHLO\n\tus-smtp-1.mimecast.com\" rhost-flags-OK-OK-OK-FAIL) by\n\tvger.kernel.org\n\twith ESMTP id S1727895AbgBPTbR (ORCPT ); \n\tSun, 16 Feb 2020 14:31:17 -0500","from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com\n\t[209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id\n\tus-mta-425-QCrIaeGdPGS8L2RgawnaJw-1; Sun, 16 Feb 2020 14:31:12 -0500","from smtp.corp.redhat.com\n\t(int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8204A107ACC7;\n\tSun, 16 Feb 2020 19:31:10 +0000 (UTC)","from krava.redhat.com (ovpn-204-28.brq.redhat.com [10.40.204.28])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id CB76F8574E;\n\tSun, 16 Feb 2020 19:31:03 +0000 (UTC)"],"From":"Jiri Olsa ","To":"Alexei Starovoitov ,\n\tDaniel Borkmann ","Cc":"netdev@vger.kernel.org, bpf@vger.kernel.org, Andrii Nakryiko\n\t, Yonghong Song , Song Liu\n\t, Martin KaFai Lau ,\n\tJakub Kicinski , David Miller ,\n\t=?utf-8?b?QmrDtnJuIFTDtnBlbA==?= ,\n\tJohn Fastabend , Jesper Dangaard Brouer\n\t, Arnaldo Carvalho de Melo ","Subject":"[PATCH 10/18] bpf: Re-initialize lnode in bpf_ksym_del","Date":"Sun, 16 Feb 2020 20:29:57 +0100","Message-Id":"<20200216193005.144157-11-jolsa@kernel.org>","In-Reply-To":"<20200216193005.144157-1-jolsa@kernel.org>","References":"<20200216193005.144157-1-jolsa@kernel.org>","MIME-Version":"1.0","X-Scanned-By":"MIMEDefang 2.79 on 10.5.11.11","X-MC-Unique":"QCrIaeGdPGS8L2RgawnaJw-1","X-Mimecast-Spam-Score":"0","X-Mimecast-Originator":"kernel.org","Content-Type":"text/plain; charset=WINDOWS-1252","Content-Transfer-Encoding":"8BIT","Sender":"bpf-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"bpf@vger.kernel.org"},"content":"When bpf_prog is removed from kallsyms it's on the way\nout to be removed, so we don't care about lnode state.\n\nHowever the bpf_ksym_del will be used also by bpf_trampoline\nand bpf_dispatcher objects, which stay allocated even when\nthey are not in kallsyms list, hence the lnode re-init.\n\nThe list_del_rcu commentary states that we need to call\nsynchronize_rcu, before we can change/re-init the list_head\npointers.\n\nSigned-off-by: Jiri Olsa \n---\n kernel/bpf/core.c | 7 +++++++\n 1 file changed, 7 insertions(+)","diff":"diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c\nindex 739bef60d868..a0feba447e5d 100644\n--- a/kernel/bpf/core.c\n+++ b/kernel/bpf/core.c\n@@ -676,6 +676,13 @@ void bpf_ksym_del(struct bpf_ksym *ksym)\n \tspin_lock_bh(&bpf_lock);\n \t__bpf_ksym_del(ksym);\n \tspin_unlock_bh(&bpf_lock);\n+\n+\t/*\n+\t * As explained in list_del_rcu, We must call synchronize_rcu\n+\t * before changing list_head pointers.\n+\t */\n+\tsynchronize_rcu();\n+\tINIT_LIST_HEAD_RCU(&ksym->lnode);\n }\n \n static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)\n","prefixes":["10/18"]}