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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 DD012C83001 for ; Thu, 30 Apr 2020 08:13:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B44AD2186A for ; Thu, 30 Apr 2020 08:13:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b="pTvelUQ+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726474AbgD3INc (ORCPT ); Thu, 30 Apr 2020 04:13:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726127AbgD3INc (ORCPT ); Thu, 30 Apr 2020 04:13:32 -0400 Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com [IPv6:2a00:1450:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C4295C035495 for ; Thu, 30 Apr 2020 01:13:31 -0700 (PDT) Received: by mail-wr1-x442.google.com with SMTP id d15so5720111wrx.3 for ; Thu, 30 Apr 2020 01:13:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google; h=references:user-agent:from:to:cc:subject:in-reply-to:date :message-id:mime-version; bh=S26iDR5wiFrSlBw+/Sqtg08lFgjLtyBozvtbShjn61Y=; b=pTvelUQ+zdPy9VKa02LtKHv3qmi3+WZYYOUBtJB+GxiRulqGC7PbCYETbq1Y6bLGyO IVHO2Bar5whefojm2f+DZ5OymKBa2qS3gDxuNKlX820aNuTJai9zLENWVTXVaKskUiCc zH/JduLJfFZU74TVWC72WISGslKVUDt5Fq5kY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:references:user-agent:from:to:cc:subject :in-reply-to:date:message-id:mime-version; bh=S26iDR5wiFrSlBw+/Sqtg08lFgjLtyBozvtbShjn61Y=; b=qA3+TqhpM9q6bBv+xXSz5Nb4W80khghT7DP4M1l75knJyeBcCDJXcony6JeV4DfOwN fQJdxXG3cBM3PFUx6wPketAcqsCnq3pYB2t/yj8yCIUPWhf7gZhc1JD8tPJ2/Bug3zxu h0hH0FlQxvpQ9j9dNJxLxmzbdkB1Cw7WJHkUC35f5nBCR2ByGJNedVWZT52/xCs7X/AP 2sA7Ll4inf9jTqhlovR+h80wlE44QQvx2ZCP18GKWE9FUROLUi/JUCdrgR46J6E2/s8E mXLOJXL0+l5H3wwjrhuyhBQpl3fJvJHLx5ttIQZvjCP/T0HZbA95wKoMpB99JgufUjRs k+rw== X-Gm-Message-State: AGi0PuYwL2qKixuUzBVnANkrdA6iu8wfR1/587sVjuKzKMlV8rzkDZDe dKdh/pWlme6jIX9v7M4sK9P1Pe/r0g0= X-Google-Smtp-Source: APiQypLvst+AtmPsyQgU2WZy0y3Y0J8quxpfpb0fOzCKml+3rJRIiOzy/41XYMewpzXoV1FZ57ZFYA== X-Received: by 2002:a5d:6b8a:: with SMTP id n10mr2607952wrx.36.1588234410414; Thu, 30 Apr 2020 01:13:30 -0700 (PDT) Received: from cloudflare.com ([2a02:a310:c262:aa00:b35e:8938:2c2a:ba8b]) by smtp.gmail.com with ESMTPSA id v1sm2992098wrv.19.2020.04.30.01.13.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Apr 2020 01:13:29 -0700 (PDT) References: <20200430021436.1522502-1-andriin@fb.com> User-agent: mu4e 1.1.0; emacs 26.3 From: Jakub Sitnicki To: Andrii Nakryiko Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, ast@fb.com, daniel@iogearbox.net, andrii.nakryiko@gmail.com, kernel-team@fb.com Subject: Re: [PATCH v2 bpf-next] libbpf: fix false uninitialized variable warning In-reply-to: <20200430021436.1522502-1-andriin@fb.com> Date: Thu, 30 Apr 2020 10:13:28 +0200 Message-ID: <87imhhv1av.fsf@cloudflare.com> MIME-Version: 1.0 Content-Type: text/plain Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Thu, Apr 30, 2020 at 04:14 AM CEST, Andrii Nakryiko wrote: > Some versions of GCC falsely detect that vi might not be initialized. That's > not true, but let's silence it with NULL initialization. > > Signed-off-by: Andrii Nakryiko > --- > tools/lib/bpf/libbpf.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index d86ff8214b96..977add1b73e2 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -5003,8 +5003,8 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj, > GElf_Shdr *shdr, Elf_Data *data) > { > int i, j, nrels, new_sz, ptr_sz = sizeof(void *); > + const struct btf_var_secinfo *vi = NULL; > const struct btf_type *sec, *var, *def; > - const struct btf_var_secinfo *vi; > const struct btf_member *member; > struct bpf_map *map, *targ_map; > const char *name, *mname; Alternatively we could borrow the kernel uninitialized_var macro: include/linux/compiler-clang.h:#define uninitialized_var(x) x = *(&(x)) include/linux/compiler-gcc.h:#define uninitialized_var(x) x = x