Merge tag 'hyperv-fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv fixes from Wei Liu:
 "Two patches from Michael and Dexuan to fix vmbus hanging issues"

* tag 'hyperv-fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  Drivers: hv: vmbus: Add timeout to vmbus_wait_for_unload
  Drivers: hv: vmbus: hibernation: do not hang forever in vmbus_bus_resume()

2 files changed, 12 insertions, 4 deletions

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 591106cf58fc..1d44bb635bb8 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -731,7 +731,7 @@ static void vmbus_wait_for_unload(void)
 	void *page_addr;
 	struct hv_message *msg;
 	struct vmbus_channel_message_header *hdr;
-	u32 message_type;
+	u32 message_type, i;
 
 	/*
 	 * CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
@@ -741,8 +741,11 @@ static void vmbus_wait_for_unload(void)
 	 * functional and vmbus_unload_response() will complete
 	 * vmbus_connection.unload_event. If not, the last thing we can do is
 	 * read message pages for all CPUs directly.
+	 *
+	 * Wait no more than 10 seconds so that the panic path can't get
+	 * hung forever in case the response message isn't seen.
 	 */
-	while (1) {
+	for (i = 0; i < 1000; i++) {
 		if (completion_done(&vmbus_connection.unload_event))
 			break;
 
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 910b6e90866c..946d0aba101f 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2382,7 +2382,10 @@ static int vmbus_bus_suspend(struct device *dev)
 	if (atomic_read(&vmbus_connection.nr_chan_close_on_suspend) > 0)
 		wait_for_completion(&vmbus_connection.ready_for_suspend_event);
 
-	WARN_ON(atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) != 0);
+	if (atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) != 0) {
+		pr_err("Can not suspend due to a previous failed resuming\n");
+		return -EBUSY;
+	}
 
 	mutex_lock(&vmbus_connection.channel_mutex);
 
@@ -2456,7 +2459,9 @@ static int vmbus_bus_resume(struct device *dev)
 
 	vmbus_request_offers();
 
-	wait_for_completion(&vmbus_connection.ready_for_resume_event);
+	if (wait_for_completion_timeout(
+		&vmbus_connection.ready_for_resume_event, 10 * HZ) == 0)
+		pr_err("Some vmbus device is missing after suspending?\n");
 
 	/* Reset the event for the next suspend. */
 	reinit_completion(&vmbus_connection.ready_for_suspend_event);