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 AF9D8CAC5A7 for ; Thu, 25 Sep 2025 09:52:52 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1v1iZI-00022t-PD; Thu, 25 Sep 2025 05:47:16 -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 1v1iYu-0001Xo-O0 for qemu-devel@nongnu.org; Thu, 25 Sep 2025 05:46:55 -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 1v1iYc-0001lP-PR for qemu-devel@nongnu.org; Thu, 25 Sep 2025 05:46:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1758793591; 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=VCiJbepTzAS/un2RtpHR4Hvplf9c95e2auSHQriyqk4=; b=VW3UILIXzmiwAY4zqR6lN1RGNDPo8bBBT9sJ9+eKpZLRWYozYm6N2+Z3uEOzVMA0gLw+b5 ag6uvwFpws2fR0lB8qEW75yYVelWAeMoeSi/oPDKehbOguXQ8WR7rxAAJigTPOkN9sYUFk uHuqY8p+ddQOzCqSGqR5rx7g/Iso70o= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-517-DE_8BKf3NRuGZdH2N0NOYg-1; Thu, 25 Sep 2025 05:46:29 -0400 X-MC-Unique: DE_8BKf3NRuGZdH2N0NOYg-1 X-Mimecast-MFC-AGG-ID: DE_8BKf3NRuGZdH2N0NOYg_1758793588 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6C7031800343; Thu, 25 Sep 2025 09:46:28 +0000 (UTC) Received: from toolbx.redhat.com (unknown [10.42.28.163]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 1E0F7300021A; Thu, 25 Sep 2025 09:46:22 +0000 (UTC) From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Cc: Hanna Reitz , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Kevin Wolf , qemu-rust@nongnu.org, Richard Henderson , Markus Armbruster , Christian Schoenebeck , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , qemu-block@nongnu.org, Stefan Weil , "Dr. David Alan Gilbert" , Manos Pitsidianakis , Gerd Hoffmann , devel@lists.libvirt.org, Paolo Bonzini Subject: [PATCH v4 17/23] util: fix interleaving of error prefixes Date: Thu, 25 Sep 2025 10:44:35 +0100 Message-ID: <20250925094441.1651372-18-berrange@redhat.com> In-Reply-To: <20250925094441.1651372-1-berrange@redhat.com> References: <20250925094441.1651372-1-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 10.30.177.4 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: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.444, 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, 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: , 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. Signed-off-by: Daniel P. Berrangé --- util/error-report.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/util/error-report.c b/util/error-report.c index 222c40d0d1..b6aa20dbae 100644 --- a/util/error-report.c +++ b/util/error-report.c @@ -226,6 +226,8 @@ static void vreport(report_type type, const char *fmt, va_list ap) if (monitor_cur_is_hmp()) { cur = monitor_cur(); + } else { + flockfile(stderr); } if (message_with_timestamp && !cur) { @@ -254,6 +256,10 @@ 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) { + funlockfile(stderr); + } } /* -- 2.50.1