From mboxrd@z Thu Jan 1 00:00:00 1970 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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 2A93FC2D0CE for ; Wed, 22 Jan 2020 02:41:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E6F3C217F4 for ; Wed, 22 Jan 2020 02:41:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579660912; bh=jf83gq+/eWEf1p2lSaW9KXeSrM2R69MlmUDMljh4L3c=; h=From:To:CC:Subject:Date:List-ID:From; b=aoNczpaUwNsWKbxKXeNuRw8FdEjpdwJqkHzp7ZjNFUeK9477dfUl+G85a/yq/a2nm giOyBdxP7O/6/cx/UzgeTCXNmkgcioBoHTc24rNuZd0MBNwDcH9aVVlDjMRrWPgB1J EPKUaqZusXbAzzp4whOo2M+7UlGLKckIfdbJLyc4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728901AbgAVClv convert rfc822-to-8bit (ORCPT ); Tue, 21 Jan 2020 21:41:51 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:1132 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728809AbgAVClv (ORCPT ); Tue, 21 Jan 2020 21:41:51 -0500 Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 00M2dJrl014539 for ; Tue, 21 Jan 2020 18:41:50 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 2xp72p9st6-7 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 21 Jan 2020 18:41:50 -0800 Received: from intmgw005.03.ash8.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::d) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Tue, 21 Jan 2020 18:41:49 -0800 Received: by devbig007.ftw2.facebook.com (Postfix, from userid 572438) id 72523760C45; Tue, 21 Jan 2020 18:41:38 -0800 (PST) Smtp-Origin-Hostprefix: devbig From: Alexei Starovoitov Smtp-Origin-Hostname: devbig007.ftw2.facebook.com To: CC: , , , Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH bpf-next] bpf: Fix error path under memory pressure Date: Tue, 21 Jan 2020 18:41:38 -0800 Message-ID: <20200122024138.3385590-1-ast@kernel.org> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-01-17_05:2020-01-16,2020-01-17 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxscore=0 mlxlogscore=369 impostorscore=0 adultscore=0 suspectscore=3 bulkscore=10 spamscore=0 lowpriorityscore=10 malwarescore=0 clxscore=1034 phishscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-2001220019 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Restore the 'if (env->cur_state)' check that was incorrectly removed during code move. Under memory pressure env->cur_state can be freed and zeroed inside do_check(). Hence the check is necessary. Fixes: 51c39bb1d5d1 ("bpf: Introduce function-by-function verification") Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index ca17dccc17ba..6defbec9eb62 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -9594,8 +9594,13 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog) ret = do_check(env); out: - free_verifier_state(env->cur_state, true); - env->cur_state = NULL; + /* check for NULL is necessary, since cur_state can be freed inside + * do_check() under memory pressure. + */ + if (env->cur_state) { + free_verifier_state(env->cur_state, true); + env->cur_state = NULL; + } while (!pop_stack(env, NULL, NULL)); free_states(env); if (ret) -- 2.23.0