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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,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 85390C433E0 for ; Tue, 16 Feb 2021 16:10:55 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4A4C464DE0 for ; Tue, 16 Feb 2021 16:10:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4A4C464DE0 Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=xenproject.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.85909.160780 (Exim 4.92) (envelope-from ) id 1lC2w2-0001C8-6X; Tue, 16 Feb 2021 16:10:46 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 85909.160780; Tue, 16 Feb 2021 16:10:46 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lC2w2-0001C1-3c; Tue, 16 Feb 2021 16:10:46 +0000 Received: by outflank-mailman (input) for mailman id 85909; Tue, 16 Feb 2021 16:10:45 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lC2w1-0001Bw-CV for xen-devel@lists.xenproject.org; Tue, 16 Feb 2021 16:10:45 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lC2w1-0004A8-AJ for xen-devel@lists.xenproject.org; Tue, 16 Feb 2021 16:10:45 +0000 Received: from iwj (helo=mariner.uk.xensource.com) by xenbits.xenproject.org with local-bsmtp (Exim 4.92) (envelope-from ) id 1lC2w1-00047e-9a for xen-devel@lists.xenproject.org; Tue, 16 Feb 2021 16:10:45 +0000 Received: from iwj by mariner.uk.xensource.com with local (Exim 4.89) (envelope-from ) id 1lC2vy-0000kA-5V; Tue, 16 Feb 2021 16:10:42 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xenproject.org; s=20200302mail; h=References:In-Reply-To:Subject:Cc:To:Date :Message-ID:Content-Transfer-Encoding:Content-Type:MIME-Version:From; bh=wCbS+McCL2JPV+sCiQ+JDxAUUe/J7CsQjnJ4BiKHHJ0=; b=LipKPbop7/HxsqHVOmxneAfClf bEF64tAnQiNlzTRbSazo08aNM/NACpUmD2fZ79gcqi5e9Vr6pikwchvyMztnsuw8XQaZZKqkvl+gs dR5kY8P7KasM7uoHD4LMfmqIci3YyS8qwnjcx0AKU0wJAjyCF1ozYF5aezEMU1xQWkBI=; From: Ian Jackson MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Message-ID: <24619.61057.971290.452710@mariner.uk.xensource.com> Date: Tue, 16 Feb 2021 16:10:41 +0000 To: Andrew Cooper Cc: Xen-devel , Wei Liu , Juergen Gross Subject: Re: [PATCH 06/10] stubdom/xenstored: Fix uninitialised variables in lu_read_state() In-Reply-To: <20210212153953.4582-7-andrew.cooper3@citrix.com> References: <20210212153953.4582-1-andrew.cooper3@citrix.com> <20210212153953.4582-7-andrew.cooper3@citrix.com> X-Mailer: VM 8.2.0b under 24.5.1 (i686-pc-linux-gnu) Andrew Cooper writes ("[PATCH 06/10] stubdom/xenstored: Fix uninitialised variables in lu_read_state()"): > Various version of gcc, when compiling with -Og, complain: > > xenstored_control.c: In function ‘lu_read_state’: > xenstored_control.c:540:11: error: ‘state.size’ is used uninitialized in this > function [-Werror=uninitialized] > if (state.size == 0) > ~~~~~^~~~~ > xenstored_control.c:543:6: error: ‘state.buf’ may be used uninitialized in > this function [-Werror=maybe-uninitialized] > pre = state.buf; > ~~~~^~~~~~~~~~~ > xenstored_control.c:550:23: error: ‘state.buf’ may be used uninitialized in > this function [-Werror=maybe-uninitialized] > (void *)head - state.buf < state.size; > ~~~~~^~~~ > xenstored_control.c:550:35: error: ‘state.size’ may be used uninitialized in > this function [-Werror=maybe-uninitialized] > (void *)head - state.buf < state.size; > ~~~~~^~~~~ > > Interestingly, this is only in the stubdom build. I can't identify any > relevant differences vs the regular tools build. #ifdef __MINIOS__ static void lu_get_dump_state(struct lu_dump_state *state) { } So the compiler is right to complain that lu_get_dump_state(&state); if (state.size == 0) barf_perror("No state found after live-update"); this will use state.size uninitialised. It's probably just luck that this works at all, if it does, anywhere... Reviewed-by: Ian Jackson Release-Acked-by: Ian Jackson Ian.