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Tue, 03 Mar 2020 02:08:09 +0000 Received: from abhmp0002.oracle.com (abhmp0002.oracle.com [141.146.116.8]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 023288ms023929; Tue, 3 Mar 2020 02:08:08 GMT Received: from localhost.localdomain (/10.211.9.80) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 02 Mar 2020 18:08:08 -0800 From: Dongli Zhang To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Date: Mon, 2 Mar 2020 17:58:59 -0800 Message-Id: <20200303015859.18813-2-dongli.zhang@oracle.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200303015859.18813-1-dongli.zhang@oracle.com> References: <20200303015859.18813-1-dongli.zhang@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9548 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 phishscore=0 suspectscore=0 malwarescore=0 mlxlogscore=976 mlxscore=0 spamscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2003030013 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9548 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 mlxscore=0 bulkscore=0 adultscore=0 suspectscore=0 spamscore=0 malwarescore=0 impostorscore=0 priorityscore=1501 mlxlogscore=999 lowpriorityscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2003030013 Subject: [Xen-devel] [PATCH 2/2] xenbus: req->err should be updated before req->state X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: jgross@suse.com, boris.ostrovsky@oracle.com, sstabellini@kernel.org, joe.jin@oracle.com MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" 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 --- 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 852ed161fc2a..eb5151fc8efa 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); }