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 lists1p.gnu.org (lists1p.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 20D70C43458 for ; Tue, 30 Jun 2026 09:00:37 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1weUK0-0006Xx-Si; Tue, 30 Jun 2026 05:00:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1weUJx-0006XG-NO for qemu-devel@nongnu.org; Tue, 30 Jun 2026 04:59:57 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1weUJw-0005WB-6V for qemu-devel@nongnu.org; Tue, 30 Jun 2026 04:59:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1782809994; 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=UUpTSXigTNe0YckeQ03uIUKeCd/qvqZ81pCSCFyNnLQ=; b=LeqqGDdDJGcPFtU2LOXSA118bdn1fk9s5LpzVbRqB1WYru6KjnEXvTTfbOSySS33kZe7Xj zjvVe/Dq80JydQaXGOuDAZ/JOWeO4MW9XDYNebVEFpok8C1j8tHPAmoLCCJoasvYgl7Odd nqlAceDak5nvfeCoPgzXXpieII+spKk= Received: from mx-prod-mc-05.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-301-mF5xtWYnMeqZhC2iQ0pkeg-1; Tue, 30 Jun 2026 04:59:51 -0400 X-MC-Unique: mF5xtWYnMeqZhC2iQ0pkeg-1 X-Mimecast-MFC-AGG-ID: mF5xtWYnMeqZhC2iQ0pkeg_1782809991 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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C9D0C1956047; Tue, 30 Jun 2026 08:59:50 +0000 (UTC) Received: from redhat.com (unknown [10.44.50.20]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3A0FC195608E; Tue, 30 Jun 2026 08:59:48 +0000 (UTC) Date: Tue, 30 Jun 2026 09:59:45 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Peter Maydell Cc: qemu-devel@nongnu.org, "Maciej S . Szmigiero" Subject: Re: [PATCH] hw/hyperv: Avoid crash if hyperv_find_cpu() passed invalid vp_index Message-ID: References: <20260630084855.2319838-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260630084855.2319838-1-peter.maydell@linaro.org> User-Agent: Mutt/2.3.2 (2026-04-26) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 8 X-Spam_score: 0.8 X-Spam_bar: / X-Spam_report: (0.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.445, 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development 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, Jun 30, 2026 at 09:48:55AM +0100, Peter Maydell wrote: > The hyperv_find_cpu() function finds a CPU from a CPU index; this is > basically a wrapper around qemu_get_cpu(). It is allowed to fail, in > which case it returns NULL, which its caller handles. However, it > includes an assertion check which accidentally assumes the CPU > pointer is non-NULL. > > We could assert only if cs != NULL, but the assertion here is not > doing anything interesting -- hyperv_vp_index() is a trivial wrapper > returning cs->cpu_index, so this is effectively asserting that > qemu_get_cpu() did what it claims to do, i.e. returned us the CPU > matching the index we gave it. qemu_get_cpu() is a simple "iterate > through list and find matching CPU" which is unlikely to be buggy, > and we don't feel the need to sanity-check it in any of our other > many uses of it. Drop the assertion entirely. > > Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3568 > Signed-off-by: Peter Maydell > --- > Checked only with make check / check-functional... > --- > hw/hyperv/hyperv.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) Reviewed-by: Daniel P. Berrangé With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|