When a Linux hv_sock app tries to connect to a Service GUID on which no
host app is listening, a recent host (RS3+) sends a
CHANNELMSG_TL_CONNECT_RESULT (23) message to Linux and this triggers such
a warning:
unknown msgtype=23
WARNING: CPU: 2 PID: 0 at drivers/hv/vmbus_drv.c:1031 vmbus_on_msg_dpc
Actually Linux can safely ignore the message because the Linux app's
connect() will time out in 2 seconds: see VSOCK_DEFAULT_CONNECT_TIMEOUT
and vsock_stream_connect(). We don't bother to make use of the message
because: 1) it's only supported on recent hosts; 2) a non-trivial effort
is required to use the message in Linux, but the benefit is small.
So, let's not see the warning by silently ignoring the message.
Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
---
drivers/hv/vmbus_drv.c | 5 +++++
include/linux/hyperv.h | 2 ++
2 files changed, 7 insertions(+)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 4ef5a66df680..c838b6f5f726 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1033,6 +1033,11 @@ void vmbus_on_msg_dpc(unsigned long data)
}
entry = &channel_message_table[hdr->msgtype];
+
+ /* Linux ignores some messages, e.g. CHANNELMSG_TL_CONNECT_RESULT. */
+ if (!entry->message_handler)
+ goto msg_handled;
+
if (entry->handler_type == VMHT_BLOCKING) {
ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
if (ctx == NULL)
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 26f3aeeae1ca..41c58011431e 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -425,6 +425,8 @@ enum vmbus_channel_message_type {
CHANNELMSG_19 = 19,
CHANNELMSG_20 = 20,
CHANNELMSG_TL_CONNECT_REQUEST = 21,
+ CHANNELMSG_22 = 22,
+ CHANNELMSG_TL_CONNECT_RESULT = 23,
CHANNELMSG_COUNT
};
--
2.19.1
