Make kvp_register() return an error code instead of silently ignoring
failures, and propagate the error from kvp_handle_handshake() instead of
returning success.

This propagates both kzalloc_obj() and hvutil_transport_send() failures
to kvp_handle_handshake() and thus to kvp_on_msg().

Fixes: 245ba56a52a3 ("Staging: hv: Implement key/value pair (KVP)")
Cc: stable@vger.kernel.org
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
 drivers/hv/hv_kvp.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index 0d73daf745a7..6180ebe040ff 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -93,7 +93,7 @@ static void kvp_send_key(struct work_struct *dummy);
 static void kvp_respond_to_host(struct hv_kvp_msg *msg, int error);
 static void kvp_timeout_func(struct work_struct *dummy);
 static void kvp_host_handshake_func(struct work_struct *dummy);
-static void kvp_register(int);
+static int kvp_register(int);
 
 static DECLARE_DELAYED_WORK(kvp_timeout_work, kvp_timeout_func);
 static DECLARE_DELAYED_WORK(kvp_host_handshake_work, kvp_host_handshake_func);
@@ -127,24 +127,26 @@ static void kvp_register_done(void)
 	hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
 }
 
-static void
+static int
 kvp_register(int reg_value)
 {
 
 	struct hv_kvp_msg *kvp_msg;
 	char *version;
+	int ret;
 
 	kvp_msg = kzalloc_obj(*kvp_msg);
+	if (!kvp_msg)
+		return -ENOMEM;
 
-	if (kvp_msg) {
-		version = kvp_msg->body.kvp_register.version;
-		kvp_msg->kvp_hdr.operation = reg_value;
-		strcpy(version, HV_DRV_VERSION);
+	version = kvp_msg->body.kvp_register.version;
+	kvp_msg->kvp_hdr.operation = reg_value;
+	strcpy(version, HV_DRV_VERSION);
 
-		hvutil_transport_send(hvt, kvp_msg, sizeof(*kvp_msg),
-				      kvp_register_done);
-		kfree(kvp_msg);
-	}
+	ret = hvutil_transport_send(hvt, kvp_msg, sizeof(*kvp_msg),
+				    kvp_register_done);
+	kfree(kvp_msg);
+	return ret;
 }
 
 static void kvp_timeout_func(struct work_struct *dummy)
@@ -186,9 +188,8 @@ static int kvp_handle_handshake(struct hv_kvp_msg *msg)
 	 */
 	pr_debug("KVP: userspace daemon ver. %d connected\n",
 		 msg->kvp_hdr.operation);
-	kvp_register(dm_reg_value);
 
-	return 0;
+	return kvp_register(dm_reg_value);
 }

Tue, 14 Apr 2026 13:10:08 +0200 Thorsten Blum <thorsten.blum@linux.dev>:

> Fixes: 245ba56a52a3 ("Staging: hv: Implement key/value pair (KVP)")

Please do not abuse the Fixes tag when it fact this change is "cosmetics".


Olaf

On Wed, Apr 29, 2026 at 02:27:24PM +0200, Olaf Hering wrote:
> Tue, 14 Apr 2026 13:10:08 +0200 Thorsten Blum <thorsten.blum@linux.dev>:
> 
> > Fixes: 245ba56a52a3 ("Staging: hv: Implement key/value pair (KVP)")
> 
> Please do not abuse the Fixes tag when it fact this change is "cosmetics".

What makes you think this is just "cosmetics"?

Wed, 29 Apr 2026 14:36:36 +0200 Thorsten Blum <thorsten.blum@linux.dev>:

> What makes you think this is just "cosmetics"?

It does fix an unlikely bug indeed, but it does not need to trigger the whole paperwork attached to a Fixes tag.


Olaf