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 5F000C4332F for ; Wed, 14 Dec 2022 13:58:02 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p5S6B-0006Gh-Ne; Wed, 14 Dec 2022 08:47:03 -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 1p5S58-0004kq-6W for qemu-devel@nongnu.org; Wed, 14 Dec 2022 08:45:58 -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 1p5S55-0003i0-Jg for qemu-devel@nongnu.org; Wed, 14 Dec 2022 08:45:57 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1671025555; 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: in-reply-to:in-reply-to:references:references; bh=IzsAC5kclVuvqsbygy1C3OJpPhyxKHbwIPx49HYFFso=; b=RNYku/z/BQy/kzl1P4HYrIGRf1G6nFlm/IG7RYi0zLpD7HQAwLGUtnmxi43QjncWfgk4aS 3PPzE6uL0pVM4cyH9d5dJ1ahy9YXad/xhVIalN80TsQcVUUDgD2zsGu2CG3UgGq2q2v7Ke o9BtO5ActejI5CMmEPa9ESPwxIVYN8Y= 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-438-WTCzME9mOzKBadGsHGgQYA-1; Wed, 14 Dec 2022 08:45:51 -0500 X-MC-Unique: WTCzME9mOzKBadGsHGgQYA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 401A72A5956F; Wed, 14 Dec 2022 13:45:51 +0000 (UTC) Received: from merkur.redhat.com (unknown [10.39.194.243]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7A045140E949; Wed, 14 Dec 2022 13:45:50 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org Subject: [PULL 43/51] block: Fix locking in external_snapshot_prepare() Date: Wed, 14 Dec 2022 14:44:45 +0100 Message-Id: <20221214134453.31665-44-kwolf@redhat.com> In-Reply-To: <20221214134453.31665-1-kwolf@redhat.com> References: <20221214134453.31665-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.133.124; 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=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: 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 bdrv_img_create() polls internally (when calling bdrv_create(), which is a co_wrapper), so it can't be called while holding the lock of any AioContext except the current one without causing deadlocks. Drop the lock around the call in external_snapshot_prepare(). Signed-off-by: Kevin Wolf Message-Id: <20221207131838.239125-11-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito Signed-off-by: Kevin Wolf --- block.c | 4 ++++ blockdev.c | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/block.c b/block.c index 6191ac1f44..44d59362d6 100644 --- a/block.c +++ b/block.c @@ -6924,6 +6924,10 @@ bool bdrv_op_blocker_is_empty(BlockDriverState *bs) return true; } +/* + * Must not be called while holding the lock of an AioContext other than the + * current one. + */ void bdrv_img_create(const char *filename, const char *fmt, const char *base_filename, const char *base_fmt, char *options, uint64_t img_size, int flags, bool quiet, diff --git a/blockdev.c b/blockdev.c index 8ffb3d9537..011e48df7b 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1524,10 +1524,14 @@ static void external_snapshot_prepare(BlkActionState *common, goto out; } bdrv_refresh_filename(state->old_bs); + + aio_context_release(aio_context); bdrv_img_create(new_image_file, format, state->old_bs->filename, state->old_bs->drv->format_name, NULL, size, flags, false, &local_err); + aio_context_acquire(aio_context); + if (local_err) { error_propagate(errp, local_err); goto out; -- 2.38.1