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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 80796C87FC9 for ; Tue, 29 Jul 2025 13:17:46 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ugkCy-00011T-38; Tue, 29 Jul 2025 09:17:32 -0400 Received: from eggs.gnu.org ([209.51.188.92]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ugkCi-0000Un-3X for qemu-devel@nongnu.org; Tue, 29 Jul 2025 09:17:22 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ugkCe-0002ZT-Bq for qemu-devel@nongnu.org; Tue, 29 Jul 2025 09:17:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1753795027; h=from:from:reply-to: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=A46pdvu3P8sVMAVxEZjlM/QkpXNT6aCO2+WxlHevqcU=; b=PaS5lV/59jb1RqUVRD8NVLjttjLmSGeD5/mAyzBaHnaGVuXd28DZpblW4/wzoIisOkISBb wH5xcIbiOdBOSdy6fdjYpLoJYOW+aySeOtxe3etZUjfODcfE3q0Actr5wHVBGK4prTbzu8 jsypydUTt4uuSFZt9GhSKWIHzB2B/BI= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-314-HNYTd7FgNs2GY06vlk4H_Q-1; Tue, 29 Jul 2025 09:17:04 -0400 X-MC-Unique: HNYTd7FgNs2GY06vlk4H_Q-1 X-Mimecast-MFC-AGG-ID: HNYTd7FgNs2GY06vlk4H_Q_1753795023 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0F1631956089; Tue, 29 Jul 2025 13:17:03 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.12]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 43CFF19560A2; Tue, 29 Jul 2025 13:17:00 +0000 (UTC) Date: Tue, 29 Jul 2025 14:16:56 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Cc: Markus Armbruster , qemu-devel@nongnu.org, sstabellini@kernel.org, anthony@xenproject.org, paul@xen.org, edgar.iglesias@gmail.com, xen-devel@lists.xenproject.org, qemu-trivial@nongnu.org Subject: Re: [PATCH] hw/display/xenfb: Replace unreachable code by abort() Message-ID: References: <20250729111226.3627499-1-armbru@redhat.com> <14fff91b-7434-4d90-adb1-ebbe3f51d605@linaro.org> <87v7nbdwfx.fsf@pond.sub.org> <15536eea-5a66-4dff-b4bd-8a43fbfa9365@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <15536eea-5a66-4dff-b4bd-8a43fbfa9365@linaro.org> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Jul 29, 2025 at 02:59:46PM +0200, Philippe Mathieu-Daudé wrote: > On 29/7/25 14:16, Markus Armbruster wrote: > > Philippe Mathieu-Daudé writes: > > > > > On 29/7/25 13:12, Markus Armbruster wrote: > > > > xenfb_mouse_event() has a switch statement whose controlling > > > > expression move->axis is an enum InputAxis. The enum values are > > > > INPUT_AXIS_X and INPUT_AXIS_Y, encoded as 0 and 1. The switch has a > > > > case for both axes. In addition, it has an unreachable default label. > > > > This convinces Coverity that move->axis can be greater than 1. It > > > > duly reports a buffer overrun when it is used to subscript an array > > > > with two elements. > > > > Replace the unreachable code by abort(). > > > > Resolves: Coverity CID 1613906 > > > > Signed-off-by: Markus Armbruster > > > > --- > > > > hw/display/xenfb.c | 3 +-- > > > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/hw/display/xenfb.c b/hw/display/xenfb.c > > > > index 22822fecea..5e6c691779 100644 > > > > --- a/hw/display/xenfb.c > > > > +++ b/hw/display/xenfb.c > > > > @@ -283,8 +283,7 @@ static void xenfb_mouse_event(DeviceState *dev, QemuConsole *src, > > > > scale = surface_height(surface) - 1; > > > > break; > > > > default: > > > > - scale = 0x8000; > > > > - break; > > > > + abort(); > > > > > > We prefer GLib g_assert_not_reached() over abort() because it displays > > > the file, line number & function before aborting. > > > > The purpose of this line is to tell the compiler we can't get there, > > with the least amount of ceremony. > > > > We have ~600 calls of abort(). > > And ~1600 of g_assert_not_reached() =) > > $ git grep -w 'abort();' | wc -l > 556 > $ git grep -w 'g_assert_not_reached();' | wc -l > 1551 Sounds like we could create a gitlab issue for "replace abort with g_assert_not_reached" that could be a easy on-ramp for someone to start contributing. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|