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 22279CC6B12 for ; Tue, 13 Oct 2026 15:01:17 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1xGdzH-000782-Fs; Tue, 13 Oct 2026 11:00:19 -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 1xGdzF-00076s-7Y for qemu-devel@nongnu.org; Tue, 13 Oct 2026 11:00:17 -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 1xGdzB-0007X5-Vr for qemu-devel@nongnu.org; Tue, 13 Oct 2026 11:00:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1791903613; 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: in-reply-to:in-reply-to:references:references; bh=BRhH9I83JFwlSgyiWhq+Jj2IVq/3j5+7q64OpozDJzo=; b=Hvj3QoyPIpdqtJ32qfBJJ/0WCuwwc6kHxkKj62wvCU2xcQiREVcS0F557BdL6Pb5kFUdaP Ik6HwPA2J9gBBkFSgGCkUWJu54V3upLkPKELdsNWePQ5kpOKOsIAKafgIJaSs6kdDgdZSn pLyZ6VbhZwjWUKgMYpaudBij7BYv7Fg= Received: from mx-prod-mc-06.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-479-IN_O7ICbOg2x_37JkFTWZQ-1; Tue, 13 Oct 2026 15:00:10 +0000 X-MC-Unique: IN_O7ICbOg2x_37JkFTWZQ-1 X-Mimecast-MFC-AGG-ID: IN_O7ICbOg2x_37JkFTWZQ_1791903609 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CEA62182A138; Tue, 13 Oct 2026 15:00:08 +0000 (UTC) Received: from redhat.com (headnet03.pony-001.prod.iad2.dc.redhat.com [10.2.32.114]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A07671955F73; Tue, 13 Oct 2026 15:00:06 +0000 (UTC) Date: Tue, 13 Oct 2026 10:00:04 -0500 From: Eric Blake To: Richard Henderson Cc: qemu-devel@nongnu.org, Vladimir Sementsov-Ogievskiy , Pierrick Bouvier , Kevin Wolf , Hanna Reitz , "open list:Network Block Dev..." Subject: Re: [PULL 02/15] qemu-nbd: Support -s and -l at the same time Message-ID: References: <20261008131216.2437896-17-eblake@redhat.com> <20261008131216.2437896-19-eblake@redhat.com> <45a86ce8-6db9-4636-b64f-577469a50901@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45a86ce8-6db9-4636-b64f-577469a50901@linaro.org> User-Agent: NeoMutt/20260616 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.129.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.24, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 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: 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 On Fri, Oct 09, 2026 at 12:40:59PM +0200, Richard Henderson wrote: > On 10/8/26 15:11, Eric Blake wrote: > > @@ -1155,13 +1165,17 @@ int main(int argc, char **argv) > > > > blk_set_enable_write_cache(blk, !writethrough); > > > > + orig_bs = bs; > > + if (flags & BDRV_O_SNAPSHOT) { > > + orig_bs = bs->backing->bs; > > + } > > tsan complains: > > ../qemu-nbd.c:1170:23: error: reading variable 'backing' requires holding > mutex 'graph_lock' [-Werror,-Wthread-safety-analysis] > > https://gitlab.com/qemu-project/qemu/-/jobs/17055360066 Thanks for the heads up. I got a TSAN build working on my environment, fixed up the problem, and posted a v2 pull request. -- Eric Blake, Principal Software Engineer Red Hat, Inc. Virtualization: qemu.org | libguestfs.org