[PATCH 1/1] Drivers: hv: Don't reset VMBus connection state on error/exit paths

[Michael Kelley]

In two places, current code forces vmbus_connection.conn_state to
DISCONNECTED prior to calling vmbus_disconnect(). But vmbus_disconnect()
calls vmbus_initiate_unload(), which unloads the VMBus connection
only if the conn_state is CONNECTED. Consequently, the connection
remains and the Hyper-V host might continue to send messages or post
VMBus interrupts.

The problem was introduced in commit 74347a99e73ae ("x86/Hyper-V:
Unload vmbus channel in hv panic callback"), in that
vmbus_initiate_unload() started checking the current connection
state before doing the unload. This commit removed some occurrences
where conn_state was forced to DISCONNECTED, but these two remained,
apparently due to an oversight at the time.

Fix this by not forcing conn_state to DISCONNECTED during VMBus exit,
or if a failure occurs when establishing the connection in the first
place. Whatever value conn_state has at the time is then read by
vmbus_initiate_unload() to determine if there is a connection to
be unloaded.

Reported-by: Sashiko <sashiko-bot@xxxxxxxxxx>
Closes: https://lore.kernel.org/linux-hyperv/20260805205806.B5AC31F000E9@xxxxxxxxxxxxxxx/
Fixes: 74347a99e73ae ("x86/Hyper-V: Unload vmbus channel in hv panic callback")
Signed-off-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
---
 drivers/hv/connection.c | 1 -
 drivers/hv/vmbus_drv.c  | 1 -
 2 files changed, 2 deletions(-)

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 1ab3581b096a..818667ef9c74 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -346,7 +346,6 @@ int vmbus_connect(void)
 cleanup:
 	pr_err("Unable to connect to host\n");
 
-	vmbus_connection.conn_state = DISCONNECTED;
 	vmbus_disconnect();
 
 	kfree(msginfo);
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 5ebdbe24b5a1..547bc731114f 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -3043,7 +3043,6 @@ static void __exit vmbus_exit(void)
 
 	hv_remove_kexec_handler();
 	hv_remove_crash_handler();
-	vmbus_connection.conn_state = DISCONNECTED;
 	hv_stimer_global_cleanup();
 	vmbus_disconnect();
 	if (vmbus_irq == -1)
-- 
2.25.1