From patchwork Wed Apr 1 16:16:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 228352 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 B4041C2D0F2 for ; Wed, 1 Apr 2020 16:50:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 611C520714 for ; Wed, 1 Apr 2020 16:50:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585759826; bh=hcTIdJiCXvD/krcQTIT1ht5ObWgrP9GQXXZnj8Jlw7w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nmn/r3pqG8JRHHVIWqyFPX0bZQQhi/FiGJYBpZkEL96k/tbhAc/Q2G5OFwoZrlKJ7 yTwQd0EH1EqAblQC+uWPB2rK9pi51Yu1YfxZ2yCIjhtnruy7TIjfBKaE6LoYVWYlWY VOLXEQZZiwU+US3/Uf4zR031kpLbOlInjmDYHxaI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389051AbgDAQkW (ORCPT ); Wed, 1 Apr 2020 12:40:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:40500 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389041AbgDAQkU (ORCPT ); Wed, 1 Apr 2020 12:40:20 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9CD932063A; Wed, 1 Apr 2020 16:40:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585759219; bh=hcTIdJiCXvD/krcQTIT1ht5ObWgrP9GQXXZnj8Jlw7w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U1ZPHvn2fUrb4XIP7pH7nfSjZLxgFXxG1Cw1GLnt79fr2CLfF/PIt4bjEGsUVE+Es JK3rbNehlgNNOQCh54DV7KWMfdCTJYjf0f+x2IqhvoHOSwGjb39UAJor8eeCR2WkKE aBpjgaNWHnxaJmxrNG4V5qDvpkB9mYUOKuQ1FQV4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dongli Zhang , Julien Grall , Boris Ostrovsky , Sasha Levin Subject: [PATCH 4.14 012/148] xenbus: req->err should be updated before req->state Date: Wed, 1 Apr 2020 18:16:44 +0200 Message-Id: <20200401161553.400413476@linuxfoundation.org> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200401161552.245876366@linuxfoundation.org> References: <20200401161552.245876366@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Dongli Zhang [ Upstream commit 8130b9d5b5abf26f9927b487c15319a187775f34 ] This patch adds the barrier to guarantee that req->err is always updated before req->state. Otherwise, read_reply() would not return ERR_PTR(req->err) but req->body, when process_writes()->xb_write() is failed. Signed-off-by: Dongli Zhang Link: https://lore.kernel.org/r/20200303221423.21962-2-dongli.zhang@oracle.com Reviewed-by: Julien Grall Signed-off-by: Boris Ostrovsky Signed-off-by: Sasha Levin --- drivers/xen/xenbus/xenbus_comms.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c index 852ed161fc2a7..eb5151fc8efab 100644 --- a/drivers/xen/xenbus/xenbus_comms.c +++ b/drivers/xen/xenbus/xenbus_comms.c @@ -397,6 +397,8 @@ static int process_writes(void) if (state.req->state == xb_req_state_aborted) kfree(state.req); else { + /* write err, then update state */ + virt_wmb(); state.req->state = xb_req_state_got_reply; wake_up(&state.req->wq); }