From patchwork Tue Jan 9 18:17:17 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 1884584 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=LYE7TcRX; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4T8fLq1dwmz1yP3 for ; Wed, 10 Jan 2024 05:18:27 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rNGfP-000759-3z; Tue, 09 Jan 2024 13:17:35 -0500 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 1rNGfK-00071C-Ay for qemu-devel@nongnu.org; Tue, 09 Jan 2024 13:17:30 -0500 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 1rNGfH-0007up-TQ for qemu-devel@nongnu.org; Tue, 09 Jan 2024 13:17:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1704824246; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=2F3tfQEkz8dsB15xoODuG9mIj8K3dNgWQjWwtttjtKc=; b=LYE7TcRXleYqE1BGr0vEwJCk/Tjfv6eUnwJXKRi68kP+4KDlMGy/TDG9mYVBVb5ukZJcOG rWxyynEtUR5nmmRay+UXciZ9Awec2tEGVIuhySYA7D0qIN5rncOCLsQRa1Ob8NnIQrZiEm NGERz89RTPk1UYPm3UfyVsnSZNTLR2c= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-477-7Xsds5lYOkC9kUfk07M6Dw-1; Tue, 09 Jan 2024 13:17:25 -0500 X-MC-Unique: 7Xsds5lYOkC9kUfk07M6Dw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id D3175185A784; Tue, 9 Jan 2024 18:17:24 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.194.130]) by smtp.corp.redhat.com (Postfix) with ESMTP id D7DA13C2E; Tue, 9 Jan 2024 18:17:23 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, aliang@redhat.com, stefanha@redhat.com, armbru@redhat.com, qemu-devel@nongnu.org Subject: [PATCH] string-output-visitor: Fix (pseudo) struct handling Date: Tue, 9 Jan 2024 19:17:17 +0100 Message-ID: <20240109181717.42493-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -45 X-Spam_score: -4.6 X-Spam_bar: ---- X-Spam_report: (-4.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.493, 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=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Commit ff32bb53 tried to get minimal struct support into the string output visitor by just making it return "". Unfortunately, it forgot that the caller will still make more visitor calls for the content of the struct. If the struct is contained in a list, such as IOThreadVirtQueueMapping, in the better case its fields show up as separate list entries. In the worse case, it contains another list, and the string output visitor doesn't support nested lists and asserts that this doesn't happen. So as soon as the optional "vqs" field in IOThreadVirtQueueMapping is specified, we get a crash. This can be reproduced with the following command line: echo "info qtree" | ./qemu-system-x86_64 \ -object iothread,id=t0 \ -blockdev null-co,node-name=disk \ -device '{"driver": "virtio-blk-pci", "drive": "disk", "iothread-vq-mapping": [{"iothread": "t0", "vqs": [0]}]}' \ -monitor stdio Fix the problem by counting the nesting level of structs and ignoring any visitor calls for values (apart from start/end_struct) while we're not on the top level. Fixes: ff32bb53476539d352653f4ed56372dced73a388 Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2069 Reported-by: Aihua Liang Signed-off-by: Kevin Wolf Reviewed-by: Stefan Hajnoczi Reviewed-by: Markus Armbruster --- qapi/string-output-visitor.c | 46 ++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) diff --git a/qapi/string-output-visitor.c b/qapi/string-output-visitor.c index f0c1dea89e..5115536b15 100644 --- a/qapi/string-output-visitor.c +++ b/qapi/string-output-visitor.c @@ -65,6 +65,7 @@ struct StringOutputVisitor } range_start, range_end; GList *ranges; void *list; /* Only needed for sanity checking the caller */ + unsigned int struct_nesting; }; static StringOutputVisitor *to_sov(Visitor *v) @@ -144,6 +145,10 @@ static bool print_type_int64(Visitor *v, const char *name, int64_t *obj, StringOutputVisitor *sov = to_sov(v); GList *l; + if (sov->struct_nesting) { + return true; + } + switch (sov->list_mode) { case LM_NONE: string_output_append(sov, *obj); @@ -231,6 +236,10 @@ static bool print_type_size(Visitor *v, const char *name, uint64_t *obj, uint64_t val; char *out, *psize; + if (sov->struct_nesting) { + return true; + } + if (!sov->human) { out = g_strdup_printf("%"PRIu64, *obj); string_output_set(sov, out); @@ -250,6 +259,11 @@ static bool print_type_bool(Visitor *v, const char *name, bool *obj, Error **errp) { StringOutputVisitor *sov = to_sov(v); + + if (sov->struct_nesting) { + return true; + } + string_output_set(sov, g_strdup(*obj ? "true" : "false")); return true; } @@ -260,6 +274,10 @@ static bool print_type_str(Visitor *v, const char *name, char **obj, StringOutputVisitor *sov = to_sov(v); char *out; + if (sov->struct_nesting) { + return true; + } + if (sov->human) { out = *obj ? g_strdup_printf("\"%s\"", *obj) : g_strdup(""); } else { @@ -273,6 +291,11 @@ static bool print_type_number(Visitor *v, const char *name, double *obj, Error **errp) { StringOutputVisitor *sov = to_sov(v); + + if (sov->struct_nesting) { + return true; + } + string_output_set(sov, g_strdup_printf("%.17g", *obj)); return true; } @@ -283,6 +306,10 @@ static bool print_type_null(Visitor *v, const char *name, QNull **obj, StringOutputVisitor *sov = to_sov(v); char *out; + if (sov->struct_nesting) { + return true; + } + if (sov->human) { out = g_strdup(""); } else { @@ -295,6 +322,9 @@ static bool print_type_null(Visitor *v, const char *name, QNull **obj, static bool start_struct(Visitor *v, const char *name, void **obj, size_t size, Error **errp) { + StringOutputVisitor *sov = to_sov(v); + + sov->struct_nesting++; return true; } @@ -302,6 +332,10 @@ static void end_struct(Visitor *v, void **obj) { StringOutputVisitor *sov = to_sov(v); + if (--sov->struct_nesting) { + return; + } + /* TODO actually print struct fields */ string_output_set(sov, g_strdup("")); } @@ -312,6 +346,10 @@ start_list(Visitor *v, const char *name, GenericList **list, size_t size, { StringOutputVisitor *sov = to_sov(v); + if (sov->struct_nesting) { + return true; + } + /* we can't traverse a list in a list */ assert(sov->list_mode == LM_NONE); /* We don't support visits without a list */ @@ -329,6 +367,10 @@ static GenericList *next_list(Visitor *v, GenericList *tail, size_t size) StringOutputVisitor *sov = to_sov(v); GenericList *ret = tail->next; + if (sov->struct_nesting) { + return ret; + } + if (ret && !ret->next) { sov->list_mode = LM_END; } @@ -339,6 +381,10 @@ static void end_list(Visitor *v, void **obj) { StringOutputVisitor *sov = to_sov(v); + if (sov->struct_nesting) { + return; + } + assert(sov->list == obj); assert(sov->list_mode == LM_STARTED || sov->list_mode == LM_END ||