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From: Dongli Zhang <dongli.zhang@oracle.com>
To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
Cc: julien@xen.org, boris.ostrovsky@oracle.com, jgross@suse.com,
	sstabellini@kernel.org, joe.jin@oracle.com
Subject: [PATCH v3 2/2] xenbus: req->err should be updated before req->state
Date: Tue,  3 Mar 2020 14:14:23 -0800	[thread overview]
Message-ID: <20200303221423.21962-2-dongli.zhang@oracle.com> (raw)
In-Reply-To: <20200303221423.21962-1-dongli.zhang@oracle.com>

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 <dongli.zhang@oracle.com>
---
 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);
 	}
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
From: Dongli Zhang <dongli.zhang@oracle.com>
To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
Cc: jgross@suse.com, joe.jin@oracle.com, boris.ostrovsky@oracle.com,
	sstabellini@kernel.org, julien@xen.org
Subject: [Xen-devel] [PATCH v3 2/2] xenbus: req->err should be updated before req->state
Date: Tue,  3 Mar 2020 14:14:23 -0800	[thread overview]
Message-ID: <20200303221423.21962-2-dongli.zhang@oracle.com> (raw)
In-Reply-To: <20200303221423.21962-1-dongli.zhang@oracle.com>

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 <dongli.zhang@oracle.com>
---
 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);
 	}
-- 
2.17.1


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  reply	other threads:[~2020-03-03 22:23 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-03 22:14 [PATCH v3 1/2] xenbus: req->body should be updated before req->state Dongli Zhang
2020-03-03 22:14 ` [Xen-devel] " Dongli Zhang
2020-03-03 22:14 ` Dongli Zhang [this message]
2020-03-03 22:14   ` [Xen-devel] [PATCH v3 2/2] xenbus: req->err " Dongli Zhang
2020-03-04 13:50   ` Julien Grall
2020-03-04 13:50     ` [Xen-devel] " Julien Grall
2020-03-06 11:13   ` Boris Ostrovsky
2020-03-06 11:13     ` [Xen-devel] " Boris Ostrovsky
2020-03-04 13:50 ` [PATCH v3 1/2] xenbus: req->body " Julien Grall
2020-03-04 13:50   ` [Xen-devel] " Julien Grall

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