From patchwork Mon Jul 31 12:59:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 13334579 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 BAA08C001DC for ; Mon, 31 Jul 2023 13:00:43 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qQSVY-0007lI-G5; Mon, 31 Jul 2023 09:00:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qQSVG-0007kW-UU for qemu-devel@nongnu.org; Mon, 31 Jul 2023 09:00:03 -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 1qQSVE-0007xv-Dq for qemu-devel@nongnu.org; Mon, 31 Jul 2023 09:00:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690808399; 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; bh=qcpWBDDJOi4yLuCS/GSO1Pdlb8fB/uP6AVuMBECFsQQ=; b=F9ExWnBKV4QsNDDLwe6ufPRQyo4EGJlPuAAgXaYsrFfZFVsDST/NaJ8KuHMj5y9DUHerh0 M6WHipor31INXGmarOMinbxeeKTDzruOvPqO0sV3W814P85D83myH52FLeH2yTrUiCsx3d 6ylXuhHWxiTpZ/H/9uzC0svCQov45GE= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-423-pi-kRdmQOhy25-t3RpKKrg-1; Mon, 31 Jul 2023 08:59:56 -0400 X-MC-Unique: pi-kRdmQOhy25-t3RpKKrg-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E9FD18022EF; Mon, 31 Jul 2023 12:59:55 +0000 (UTC) Received: from gshan.redhat.com (unknown [10.64.136.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 254FF492B03; Mon, 31 Jul 2023 12:59:52 +0000 (UTC) From: Gavin Shan To: qemu-arm@nongnu.org Cc: qemu-devel@nongnu.org, pbonzini@redhat.com, peter.maydell@linaro.org, philmd@linaro.org, david@redhat.com, shan.gavin@gmail.com Subject: [PATCH v2] kvm: Fix crash due to access uninitialized kvm_state Date: Mon, 31 Jul 2023 22:59:46 +1000 Message-ID: <20230731125946.2038742-1-gshan@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Received-SPF: pass client-ip=170.10.129.124; envelope-from=gshan@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_H4=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Runs into core dump on arm64 and the backtrace extracted from the core dump is shown as below. It's caused by accessing uninitialized @kvm_state in kvm_flush_coalesced_mmio_buffer() due to commit 176d073029 ("hw/arm/virt: Use machine_memory_devices_init()"), where the machine's memory region is added earlier than before. main qemu_init configure_accelerators qemu_opts_foreach do_configure_accelerator accel_init_machine kvm_init virt_kvm_type virt_set_memmap machine_memory_devices_init memory_region_add_subregion memory_region_add_subregion_common memory_region_update_container_subregions memory_region_transaction_begin qemu_flush_coalesced_mmio_buffer kvm_flush_coalesced_mmio_buffer Fix it by bailing early in kvm_flush_coalesced_mmio_buffer() on the uninitialized @kvm_state. With this applied, no crash is observed on arm64. Fixes: 176d073029 ("hw/arm/virt: Use machine_memory_devices_init()") Signed-off-by: Gavin Shan Reviewed-by: David Hildenbrand Reviewed-by: Philippe Mathieu-Daudé --- v2: Bail early in kvm_flush_coalesced_mmio_buffer() on the uninitialized @kvm_state and improved changelog (David/Peter) --- accel/kvm/kvm-all.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 373d876c05..7b3da8dc3a 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -2812,7 +2812,7 @@ void kvm_flush_coalesced_mmio_buffer(void) { KVMState *s = kvm_state; - if (s->coalesced_flush_in_progress) { + if (!s || s->coalesced_flush_in_progress) { return; }