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=-16.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 8A6E8C43387 for ; Wed, 16 Jan 2019 16:44:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 51AC9205C9 for ; Wed, 16 Jan 2019 16:44:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Hn+c1kFo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393610AbfAPQoq (ORCPT ); Wed, 16 Jan 2019 11:44:46 -0500 Received: from mail-pf1-f202.google.com ([209.85.210.202]:38986 "EHLO mail-pf1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726329AbfAPQoq (ORCPT ); Wed, 16 Jan 2019 11:44:46 -0500 Received: by mail-pf1-f202.google.com with SMTP id 68so5064991pfr.6 for ; Wed, 16 Jan 2019 08:44:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=5pN4/Fl88bLGPZT2jvSPccMbojpMwy4dgreg0fuLlnE=; b=Hn+c1kFou+mgYv1A2/Qb38GhZMLBeRzf6ClXOj2yugy/772DV2X5nJtD74qtiWw+fs 0Gk2NDtKN4X6L5jY6VBvZZ3jrm4ngzYEafcbLR3Cyxos39d+uKpDhrN82LWxiV3EFtbN IcstrtAc73A3hRIszO5pwd9uRQ6nnFrsL50dHhP2WeGwEdDhC5By07ODKN1jqREFpFNh iKhJss2dtcszLPwTP4iCPZ86r77onl/XnnNoptLP8ghLnByqir4/u9I9BxH2eB9XI2gt Cfthfdy+tEHECzhBK9KtM0tUSnaSh0FM9HupksSETtJSsh/vUM+1Mt0A2gt29HGzVESn p2/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=5pN4/Fl88bLGPZT2jvSPccMbojpMwy4dgreg0fuLlnE=; b=pPvcHVki+poQnaFG6hnx9lDRUNBpW54c65kIQYV/USD52spQAdbRplBOWZrKP6ivbt 8URjBgy/H8rUcHY8eaSB6sluykUzZo6svvRG1AndF+baFQBB/sd/q98rw1N69BdpmE0y dqX+6MvdJxVSNtWpLD/f580qNRn6kDn4Aby4lPmzP+tkLxfClEP7L/BMpG6lPK8wXXwN 7ZkfNQ6ca871anm4WSZqTS6XDYjrYILo9qSrHmTiDMSzeWJ1afAhqwcy/0smiiR7kPnF ZAVsagMbueFoQ838Ajqvor9jSLAbO7Rq4Bt0w2ISc34EwC1fR64PovFf/Q6h58K/3uQ+ FDhw== X-Gm-Message-State: AJcUukfDv/oAPKLm2jjaRwU4rdtF37w22Zniuenp6RwammSDunPE1ch1 xKES7AXL7lYWPofudfGIgje9R9Uj X-Google-Smtp-Source: ALg8bN7SEcir3ZZ4or0Hrowv7P2xfGmw3Jj2Hpu3YVs/EzkrqUTWR7XKuKtI1YROkNm6guOvEKp70TXa X-Received: by 2002:a62:3a9b:: with SMTP id v27mr3601389pfj.9.1547657085382; Wed, 16 Jan 2019 08:44:45 -0800 (PST) Date: Wed, 16 Jan 2019 08:44:32 -0800 Message-Id: <20190116164432.102776-1-posk@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.20.1.97.g81188d93c3-goog Subject: [PATCH bpf-next] bpf: fix a (false) compiler warning From: Peter Oskolkov To: Alexei Starovoitov , Daniel Borkmann , netdev@vger.kernel.org Cc: Peter Oskolkov , Peter Oskolkov Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org An older GCC compiler complains: kernel/bpf/verifier.c: In function 'bpf_check': kernel/bpf/verifier.c:4***:13: error: 'prev_offset' may be used uninitialized in this function [-Werror=maybe-uninitialized] } else if (krecord[i].insn_offset <= prev_offset) { ^ kernel/bpf/verifier.c:4***:38: note: 'prev_offset' was declared here u32 i, nfuncs, urec_size, min_size, prev_offset; Although the comiler is wrong here, the patch makes sure that prev_offset is always initialized, just to silence the warning. Signed-off-by: Peter Oskolkov --- kernel/bpf/verifier.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 56674a7c3778..ce87198ecd01 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4997,13 +4997,14 @@ static int check_btf_func(struct bpf_verifier_env *env, const union bpf_attr *attr, union bpf_attr __user *uattr) { - u32 i, nfuncs, urec_size, min_size, prev_offset; + u32 i, nfuncs, urec_size, min_size; u32 krec_size = sizeof(struct bpf_func_info); struct bpf_func_info *krecord; const struct btf_type *type; struct bpf_prog *prog; const struct btf *btf; void __user *urecord; + u32 prev_offset = 0; int ret = 0; nfuncs = attr->func_info_cnt; --