From patchwork Tue May 19 17:11:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 282346 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MIME_BASE64_TEXT,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CDE5FC433DF for ; Tue, 19 May 2020 17:14:29 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 960B420709 for ; Tue, 19 May 2020 17:14:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="M0wx699M" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 960B420709 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:50354 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jb5oy-0007GK-Rm for qemu-devel@archiver.kernel.org; Tue, 19 May 2020 13:14:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34280) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jb5ma-0002yq-Mo for qemu-devel@nongnu.org; Tue, 19 May 2020 13:12:00 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:38920 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jb5mW-0002Vn-Vw for qemu-devel@nongnu.org; Tue, 19 May 2020 13:12:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589908315; 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=sp0y+Zg3ajzpKsP0+NwKrmoN1WDadhwx00K7pgQg8F8=; b=M0wx699MizNFBq1HYFNdWxBNgv7Et0AgRhbCXFtbP9qqFcZ8K73Ml6hUem+kpYaEx14Vct dOs0sIIFjgEQUoKl16ON4tLqVZKibedaAZaBUAwhp5tiPtVO9pnjVtZSpqaCFHsUO7U/Np QPwWzqjyAxf0JiGMVrDIkqX05plmyZU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-433-qvQAiZXwNVOduU4I477xxA-1; Tue, 19 May 2020 13:11:53 -0400 X-MC-Unique: qvQAiZXwNVOduU4I477xxA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C3A601005510; Tue, 19 May 2020 17:11:52 +0000 (UTC) Received: from localhost (ovpn-114-215.ams2.redhat.com [10.36.114.215]) by smtp.corp.redhat.com (Postfix) with ESMTP id 58E3550F54; Tue, 19 May 2020 17:11:52 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 3/7] block/nvme: don't access CQE after moving cq.head Date: Tue, 19 May 2020 18:11:34 +0100 Message-Id: <20200519171138.201667-4-stefanha@redhat.com> In-Reply-To: <20200519171138.201667-1-stefanha@redhat.com> References: <20200519171138.201667-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.120; envelope-from=stefanha@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/19 09:19:26 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -3 X-Spam_score: -0.4 X-Spam_bar: / X-Spam_report: (-0.4 / 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, MIME_BASE64_TEXT=1.741, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , qemu-block@nongnu.org, Max Reitz , Stefan Hajnoczi , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Do not access a CQE after incrementing q->cq.head and releasing q->lock. It is unlikely that this causes problems in practice but it's a latent bug. The reason why it should be safe at the moment is that completion processing is not re-entrant and the CQ doorbell isn't written until the end of nvme_process_completion(). Make this change now because QEMU expects completion processing to be re-entrant and later patches will do that. Signed-off-by: Stefan Hajnoczi --- block/nvme.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/block/nvme.c b/block/nvme.c index 5286227074..6bf58bc6aa 100644 --- a/block/nvme.c +++ b/block/nvme.c @@ -321,11 +321,14 @@ static bool nvme_process_completion(BDRVNVMeState *s, NVMeQueuePair *q) q->busy = true; assert(q->inflight >= 0); while (q->inflight) { + int ret; int16_t cid; + c = (NvmeCqe *)&q->cq.queue[q->cq.head * NVME_CQ_ENTRY_BYTES]; if ((le16_to_cpu(c->status) & 0x1) == q->cq_phase) { break; } + ret = nvme_translate_error(c); q->cq.head = (q->cq.head + 1) % NVME_QUEUE_SIZE; if (!q->cq.head) { q->cq_phase = !q->cq_phase; @@ -344,7 +347,7 @@ static bool nvme_process_completion(BDRVNVMeState *s, NVMeQueuePair *q) preq->busy = false; preq->cb = preq->opaque = NULL; qemu_mutex_unlock(&q->lock); - req.cb(req.opaque, nvme_translate_error(c)); + req.cb(req.opaque, ret); qemu_mutex_lock(&q->lock); q->inflight--; progress = true;