From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.90_1) id 1lqu8m-0001Bp-Lz for mharc-qemu-trivial@gnu.org; Wed, 09 Jun 2021 05:04:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53536) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lqu8l-0001BI-C5 for qemu-trivial@nongnu.org; Wed, 09 Jun 2021 05:04:47 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:58200) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lqu8g-0000Qo-Nv for qemu-trivial@nongnu.org; Wed, 09 Jun 2021 05:04:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623229481; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=l9H8xTumUX4s18wQ0TMGvkXpjyRdzzIBBPYCnC6PvHg=; b=gbdFLZkMax0SUpi/9gr3DYp+p98wzb/+NGaDUAXoldTYtdUKRMD5bUahZrIu1I1rbejqZT akhj2WtYUxGTCJRWKUIQhu4mAsqB1dcNneWMX3UKV/Td1jt+AD8a2pXuOTqajUysvd11uy ZwZczppy6EshqhmRFmoOY+ct4Rpqt0I= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-586-7pcaAjbMPJqPuZbgwPOVVg-1; Wed, 09 Jun 2021 05:04:39 -0400 X-MC-Unique: 7pcaAjbMPJqPuZbgwPOVVg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5EC76801B12; Wed, 9 Jun 2021 09:04:38 +0000 (UTC) Received: from redhat.com (ovpn-114-230.ams2.redhat.com [10.36.114.230]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9894010016F4; Wed, 9 Jun 2021 09:04:36 +0000 (UTC) Date: Wed, 9 Jun 2021 11:04:35 +0200 From: Kevin Wolf To: Thomas Huth Cc: Vladimir Sementsov-Ogievskiy , Miroslav Rezanina , QEMU Developers , qemu-block@nongnu.org, Max Reitz , QEMU Trivial , Cleber Rosa Subject: Re: Prevent compiler warning on block.c Message-ID: References: <1162368493.17178530.1620201543649.JavaMail.zimbra@redhat.com> <62c90da0-b2f9-7068-e84f-c13bb1527191@virtuozzo.com> <9ef22266-25e1-36df-52e9-ad5244a648dc@redhat.com> MIME-Version: 1.0 In-Reply-To: <9ef22266-25e1-36df-52e9-ad5244a648dc@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.197, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-trivial@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Jun 2021 09:04:47 -0000 Am 09.06.2021 um 09:12 hat Thomas Huth geschrieben: > On 05/05/2021 10.05, Vladimir Sementsov-Ogievskiy wrote: > > 05.05.2021 10:59, Miroslav Rezanina wrote: > > > Commit 3108a15cf (block: introduce bdrv_drop_filter()) introduced > > > uninitialized > > > variable to_cow_parent in bdrv_replace_node_common function that is > > > used only when > > > detach_subchain is true. It is used in two places. First if block > > > properly initialize > > > the variable and second block use it. > > > > > > However, compiler treats this two blocks as two independent cases so > > > it thinks first > > > block can fail test and second one pass (although both use same > > > condition). This cause > > > warning that variable can be uninitialized in second block. > > > > > > To prevent this warning, initialize the variable with NULL. > > > > > > Signed-off-by: Miroslav Rezanina > > > --- > > > diff --git a/block.c b/block.c > > > index 874c22c43e..3ca27bd2d9 100644 > > > --- a/block.c > > > +++ b/block.c > > > @@ -4851,7 +4851,7 @@ static int > > > bdrv_replace_node_common(BlockDriverState *from, > > >       Transaction *tran = tran_new(); > > >       g_autoptr(GHashTable) found = NULL; > > >       g_autoptr(GSList) refresh_list = NULL; > > > -    BlockDriverState *to_cow_parent; > > > +    BlockDriverState *to_cow_parent = NULL; > > >       int ret; > > > > > >       if (detach_subchain) { > > > > > > > Reviewed-by: Vladimir Sementsov-Ogievskiy > > This just popped up again here: > > https://lists.gnu.org/archive/html/qemu-devel/2021-06/msg02067.html > > Kevin, Max, could you please pick it up to get this problem fixed? Thanks for pinging, seems the intended refactoring hasn't happened. I've applied this one to my block branch now. Kevin 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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A2D0EC47095 for ; Wed, 9 Jun 2021 09:06:40 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 0CB0A610E6 for ; Wed, 9 Jun 2021 09:06:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0CB0A610E6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; 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bh=l9H8xTumUX4s18wQ0TMGvkXpjyRdzzIBBPYCnC6PvHg=; b=bk/r3PKhRHBkkSFBUO6zfC/63hSKFmX7kiJh7fjcFXPEUlojfznzst2v3bCNFTM8h+duvP 90e+o5XZpkm1uFJH+6UDA7EpdRrKwiuxuQ+yHExDDrqnBabx2pUlxdZEWynrJrlbGfBDw8 s5jj9Kh0ghjwbPWzSa/pwRe4YZ8DYq4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-586-7pcaAjbMPJqPuZbgwPOVVg-1; Wed, 09 Jun 2021 05:04:39 -0400 X-MC-Unique: 7pcaAjbMPJqPuZbgwPOVVg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5EC76801B12; Wed, 9 Jun 2021 09:04:38 +0000 (UTC) Received: from redhat.com (ovpn-114-230.ams2.redhat.com [10.36.114.230]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9894010016F4; Wed, 9 Jun 2021 09:04:36 +0000 (UTC) Date: Wed, 9 Jun 2021 11:04:35 +0200 From: Kevin Wolf To: Thomas Huth Subject: Re: Prevent compiler warning on block.c Message-ID: References: <1162368493.17178530.1620201543649.JavaMail.zimbra@redhat.com> <62c90da0-b2f9-7068-e84f-c13bb1527191@virtuozzo.com> <9ef22266-25e1-36df-52e9-ad5244a648dc@redhat.com> MIME-Version: 1.0 In-Reply-To: <9ef22266-25e1-36df-52e9-ad5244a648dc@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.197, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, QEMU Trivial , QEMU Developers , Max Reitz , Cleber Rosa , Miroslav Rezanina Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 09.06.2021 um 09:12 hat Thomas Huth geschrieben: > On 05/05/2021 10.05, Vladimir Sementsov-Ogievskiy wrote: > > 05.05.2021 10:59, Miroslav Rezanina wrote: > > > Commit 3108a15cf (block: introduce bdrv_drop_filter()) introduced > > > uninitialized > > > variable to_cow_parent in bdrv_replace_node_common function that is > > > used only when > > > detach_subchain is true. It is used in two places. First if block > > > properly initialize > > > the variable and second block use it. > > > > > > However, compiler treats this two blocks as two independent cases so > > > it thinks first > > > block can fail test and second one pass (although both use same > > > condition). This cause > > > warning that variable can be uninitialized in second block. > > > > > > To prevent this warning, initialize the variable with NULL. > > > > > > Signed-off-by: Miroslav Rezanina > > > --- > > > diff --git a/block.c b/block.c > > > index 874c22c43e..3ca27bd2d9 100644 > > > --- a/block.c > > > +++ b/block.c > > > @@ -4851,7 +4851,7 @@ static int > > > bdrv_replace_node_common(BlockDriverState *from, > > >       Transaction *tran = tran_new(); > > >       g_autoptr(GHashTable) found = NULL; > > >       g_autoptr(GSList) refresh_list = NULL; > > > -    BlockDriverState *to_cow_parent; > > > +    BlockDriverState *to_cow_parent = NULL; > > >       int ret; > > > > > >       if (detach_subchain) { > > > > > > > Reviewed-by: Vladimir Sementsov-Ogievskiy > > This just popped up again here: > > https://lists.gnu.org/archive/html/qemu-devel/2021-06/msg02067.html > > Kevin, Max, could you please pick it up to get this problem fixed? Thanks for pinging, seems the intended refactoring hasn't happened. I've applied this one to my block branch now. Kevin