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 <[email protected]>
---
In v2 (followed Michael Kelley's suggestions):
Removed the redundant code in vmbus_onmessage()
Added the new enries into channel_message_table[].
drivers/hv/channel_mgmt.c | 21 +++++++--------------
drivers/hv/vmbus_drv.c | 4 ++++
include/linux/hyperv.h | 2 ++
3 files changed, 13 insertions(+), 14 deletions(-)
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 8eb167540b4f..0370364169c4 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -1351,6 +1351,8 @@ channel_message_table[CHANNELMSG_COUNT] = {
{ CHANNELMSG_19, 0, NULL },
{ CHANNELMSG_20, 0, NULL },
{ CHANNELMSG_TL_CONNECT_REQUEST, 0, NULL },
+ { CHANNELMSG_22, 0, NULL },
+ { CHANNELMSG_TL_CONNECT_RESULT, 0, NULL },
};
/*
@@ -1362,25 +1364,16 @@ void vmbus_onmessage(void *context)
{
struct hv_message *msg = context;
struct vmbus_channel_message_header *hdr;
- int size;
hdr = (struct vmbus_channel_message_header *)msg->u.payload;
- size = msg->header.payload_size;
trace_vmbus_on_message(hdr);
- if (hdr->msgtype >= CHANNELMSG_COUNT) {
- pr_err("Received invalid channel message type %d size %d\n",
- hdr->msgtype, size);
- print_hex_dump_bytes("", DUMP_PREFIX_NONE,
- (unsigned char *)msg->u.payload, size);
- return;
- }
-
- if (channel_message_table[hdr->msgtype].message_handler)
- channel_message_table[hdr->msgtype].message_handler(hdr);
- else
- pr_err("Unhandled channel message type %d\n", hdr->msgtype);
+ /*
+ * vmbus_on_msg_dpc() makes sure the hdr->msgtype here can not go
+ * out of bound and the message_handler pointer can not be NULL.
+ */
+ channel_message_table[hdr->msgtype].message_handler(hdr);
}
/*
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 4ef5a66df680..029378c27421 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1033,6 +1033,10 @@ void vmbus_on_msg_dpc(unsigned long data)
}
entry = &channel_message_table[hdr->msgtype];
+
+ 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 8fa0938f9aee..692c89ccf5df 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
From: Dexuan Cui <[email protected]> Sent: Sunday, January 19, 2020 3:29 PM
>
> 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 <[email protected]>
> ---
>
> In v2 (followed Michael Kelley's suggestions):
> Removed the redundant code in vmbus_onmessage()
> Added the new enries into channel_message_table[].
>
> drivers/hv/channel_mgmt.c | 21 +++++++--------------
> drivers/hv/vmbus_drv.c | 4 ++++
> include/linux/hyperv.h | 2 ++
> 3 files changed, 13 insertions(+), 14 deletions(-)
>
Reviewed-by: Michael Kelley <[email protected]>
On Mon, Jan 20, 2020 at 12:51:51AM +0000, Michael Kelley wrote:
>From: Dexuan Cui <[email protected]> Sent: Sunday, January 19, 2020 3:29 PM
>>
>> 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 <[email protected]>
>> ---
>>
>> In v2 (followed Michael Kelley's suggestions):
>> Removed the redundant code in vmbus_onmessage()
>> Added the new enries into channel_message_table[].
>>
>> drivers/hv/channel_mgmt.c | 21 +++++++--------------
>> drivers/hv/vmbus_drv.c | 4 ++++
>> include/linux/hyperv.h | 2 ++
>> 3 files changed, 13 insertions(+), 14 deletions(-)
>>
>
>Reviewed-by: Michael Kelley <[email protected]>
Queued up, thanks!
--
Thanks,
Sasha