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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 A5752C10DCE for ; Mon, 16 Mar 2020 02:37:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 719BA20658 for ; Mon, 16 Mar 2020 02:37:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584326264; bh=hcTIdJiCXvD/krcQTIT1ht5ObWgrP9GQXXZnj8Jlw7w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=e/L6sHlqLp1t5C1hPtgeN087ORYFg1rVG9sli3wMDdaUdxEz5EcExKaA4q716Z/DB GXMwXNtPY7peiZ7Ctzamhivsk/+mzs4T/7DkOr9RD+Q0Gb1mIzZkH/kRGvIHnDXre7 xHU19bT+oHatxIOtAOxagjp+iqEYgYKgpX3K17pY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730194AbgCPChn (ORCPT ); Sun, 15 Mar 2020 22:37:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:39560 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730032AbgCPCfQ (ORCPT ); Sun, 15 Mar 2020 22:35:16 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 335CF20726; Mon, 16 Mar 2020 02:35:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584326115; bh=hcTIdJiCXvD/krcQTIT1ht5ObWgrP9GQXXZnj8Jlw7w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iBR506pJ62IzxkQpQmPFtJDAqVAO0T3jnoWtmNTuRTI1ckopUNBlrjO4wfdj1K6/T hLrIqQO4AYuQZXOaPM0rlqi1bePwZmGWMpnEdbOsHQKxBBr9F+vGs0WLR6MjQ1HqdU 5x5V9trPkIguBoikbQWDXpJayHDPVMwn7eHWKgIA= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Dongli Zhang , Julien Grall , Boris Ostrovsky , Sasha Levin , xen-devel@lists.xenproject.org Subject: [PATCH AUTOSEL 4.19 18/20] xenbus: req->err should be updated before req->state Date: Sun, 15 Mar 2020 22:34:51 -0400 Message-Id: <20200316023453.1800-18-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200316023453.1800-1-sashal@kernel.org> References: <20200316023453.1800-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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); } -- 2.20.1