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 CDA40EDA680 for ; Tue, 3 Mar 2026 15:08:36 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vxRL3-0006yg-Ps; Tue, 03 Mar 2026 10:07:09 -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 1vxRKz-0006tI-SS for qemu-devel@nongnu.org; Tue, 03 Mar 2026 10:07:06 -0500 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 1vxRKy-0002AY-4i for qemu-devel@nongnu.org; Tue, 03 Mar 2026 10:07:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1772550423; 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=juZS92eO3WbOQRVO+8U3Zr/KTbezJf4zZdiWjx2+nNY=; b=f07+CeI+3XmrzS5xPdOMfAJBrtx+n7Mz7bhsextCddXyCfH27Vc9jlGKNn8J8+XC2XOmx4 3WcjZOJlcI71oBqK/a4a3vACYOd3vHLA1mYO2ykJzVLPpVCtW8R/dxtnzgjbwQ5ZPO5Upt J0klHTZmgPEIjKpq2n/ocihm07POwuo= Received: from mx-prod-mc-03.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-172-YxSlj2CoM4644yif675QFw-1; Tue, 03 Mar 2026 10:07:01 -0500 X-MC-Unique: YxSlj2CoM4644yif675QFw-1 X-Mimecast-MFC-AGG-ID: YxSlj2CoM4644yif675QFw_1772550420 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9EE901956071; Tue, 3 Mar 2026 15:07:00 +0000 (UTC) Received: from toolbx.redhat.com (unknown [10.45.225.185]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id B1BF41800370; Tue, 3 Mar 2026 15:06:58 +0000 (UTC) From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Cc: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Markus Armbruster , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Richard Henderson Subject: [PULL 25/27] util: fix interleaving of error prefixes Date: Tue, 3 Mar 2026 15:06:02 +0000 Message-ID: <20260303150604.2402872-26-berrange@redhat.com> In-Reply-To: <20260303150604.2402872-1-berrange@redhat.com> References: <20260303150604.2402872-1-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 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: 27 X-Spam_score: 2.7 X-Spam_bar: ++ X-Spam_report: (2.7 / 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_SBL_CSS=3.335, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.322, RCVD_IN_VALIDITY_SAFE_BLOCKED=1.141, 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org The vreport() function will optionally emit an prefix for error messages which is output to stderr incrementally. In the event that two vreport() calls execute concurrently, there is a risk that the prefix output will interleave. To address this it is required to take a lock on 'stderr' when outputting errors. Reported-by: Markus Armbruster Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Richard Henderson Reviewed-by: Markus Armbruster Signed-off-by: Daniel P. Berrangé --- util/error-report.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/util/error-report.c b/util/error-report.c index 6b9e592bc1..bbea49a55d 100644 --- a/util/error-report.c +++ b/util/error-report.c @@ -233,6 +233,9 @@ static void vreport(report_type type, const char *fmt, va_list ap) if (monitor_cur_is_qmp()) { cur = NULL; } + if (!cur) { + qemu_flockfile(stderr); + } if (message_with_timestamp && !cur) { timestr = real_time_iso8601(); @@ -260,6 +263,10 @@ static void vreport(report_type type, const char *fmt, va_list ap) error_vprintf_mon(cur, fmt, ap); error_printf_mon(cur, "\n"); + + if (!cur) { + qemu_funlockfile(stderr); + } } /* -- 2.53.0