From patchwork Wed Dec 2 00:16:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 337677 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=-17.0 required=3.0 tests=BAYES_00, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 383E2C71155 for ; Wed, 2 Dec 2020 00:24:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE5092158C for ; Wed, 2 Dec 2020 00:24:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726631AbgLBAYn convert rfc822-to-8bit (ORCPT ); Tue, 1 Dec 2020 19:24:43 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:48790 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726482AbgLBAYm (ORCPT ); Tue, 1 Dec 2020 19:24:42 -0500 Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0B20GYuY021171 for ; Tue, 1 Dec 2020 16:24:02 -0800 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 3547g8qwu4-4 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 01 Dec 2020 16:24:02 -0800 Received: from intmgw001.03.ash8.facebook.com (2620:10d:c085:108::8) by mail.thefacebook.com (2620:10d:c085:11d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Tue, 1 Dec 2020 16:24:00 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id CA0E02ECA70C; Tue, 1 Dec 2020 16:23:57 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , , Martin KaFai Lau Subject: [PATCH v4 bpf-next 01/14] bpf: fix bpf_put_raw_tracepoint()'s use of __module_address() Date: Tue, 1 Dec 2020 16:16:03 -0800 Message-ID: <20201202001616.3378929-2-andrii@kernel.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201202001616.3378929-1-andrii@kernel.org> References: <20201202001616.3378929-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312, 18.0.737 definitions=2020-12-01_12:2020-11-30,2020-12-01 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 bulkscore=0 clxscore=1034 spamscore=0 suspectscore=8 phishscore=0 mlxscore=0 impostorscore=0 lowpriorityscore=0 malwarescore=0 mlxlogscore=789 priorityscore=1501 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012020000 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org __module_address() needs to be called with preemption disabled or with module_mutex taken. preempt_disable() is enough for read-only uses, which is what this fix does. Also, module_put() does internal check for NULL, so drop it as well. Fixes: a38d1107f937 ("bpf: support raw tracepoints in modules") Acked-by: Martin KaFai Lau Signed-off-by: Andrii Nakryiko --- kernel/trace/bpf_trace.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index d255bc9b2bfa..23a390aac524 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2060,10 +2060,12 @@ struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name) void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp) { - struct module *mod = __module_address((unsigned long)btp); + struct module *mod; - if (mod) - module_put(mod); + preempt_disable(); + mod = __module_address((unsigned long)btp); + module_put(mod); + preempt_enable(); } static __always_inline