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 5A637C636D4 for ; Wed, 15 Feb 2023 11:48:53 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pSGH3-0003co-VO; Wed, 15 Feb 2023 06:48:33 -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 1pSGH2-0003cE-5k for qemu-devel@nongnu.org; Wed, 15 Feb 2023 06:48:32 -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 1pSGH0-0001o5-2s for qemu-devel@nongnu.org; Wed, 15 Feb 2023 06:48:31 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1676461708; 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=lyFpfhmDv0IdPdcN7WJRFvoKxaRlZPW58GQKDqVDuto=; b=TU/YJo2IG3l8f9njt81ja8PvwwG6tVcDa16YWZ1UlWRpMikxTwp6jusmzPf7QIZ/sKTuJW 23ME2CzyWJxfDW90NkM5YrVgVfVBI2NVO62NXfRkoD9Hw21MD+Um07bB0YVGiK0MRah6zd JDS87ljgnpIgGE0nswxNQZB39etygM0= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-49-T5XovjVBOuy9lhYd7wut4w-1; Wed, 15 Feb 2023 06:48:27 -0500 X-MC-Unique: T5XovjVBOuy9lhYd7wut4w-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C63D629A9CB0; Wed, 15 Feb 2023 11:48:25 +0000 (UTC) Received: from redhat.com (unknown [10.39.194.224]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E14042166B30; Wed, 15 Feb 2023 11:48:24 +0000 (UTC) Date: Wed, 15 Feb 2023 12:48:23 +0100 From: Kevin Wolf To: Stefano Garzarella Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, Hanna Reitz , Aihua Liang Subject: Re: [PATCH v2] block: temporarily hold the new AioContext of bs_top in bdrv_append() Message-ID: References: <20230214171621.11574-1-sgarzare@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230214171621.11574-1-sgarzare@redhat.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 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: -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_H2=-0.001, SPF_HELO_NONE=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 Am 14.02.2023 um 18:16 hat Stefano Garzarella geschrieben: > bdrv_append() is called with bs_top AioContext held, but > bdrv_attach_child_noperm() could change the AioContext of bs_top. > > bdrv_replace_node_noperm() calls bdrv_drained_begin() starting from > commit 2398747128 ("block: Don't poll in bdrv_replace_child_noperm()"). > bdrv_drained_begin() can call BDRV_POLL_WHILE that assumes the new lock > is taken, so let's temporarily hold the new AioContext to prevent QEMU > from failing in BDRV_POLL_WHILE when it tries to release the wrong > AioContext. > > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2168209 > Reported-by: Aihua Liang > Signed-off-by: Stefano Garzarella Thanks, applied to the block branch. Kevin