[PATCH 2/4] x86/Hyper-V: Free hv_panic_page when fail to register kmsg dump

[ltykernel]

From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>

If fail to register kmsg dump on Hyper-V platform, hv_panic_page
will not be used anywhere. So free and reset it.

Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
---
 drivers/hv/vmbus_drv.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index b56b9fb9bd90..b043efea092a 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1385,9 +1385,13 @@ static int vmbus_bus_init(void)
 			hv_panic_page = (void *)hv_alloc_hyperv_zeroed_page();
 			if (hv_panic_page) {
 				ret = kmsg_dump_register(&hv_kmsg_dumper);
-				if (ret)
+				if (ret) {
 					pr_err("Hyper-V: kmsg dump register "
 						"error 0x%x\n", ret);
+					hv_free_hyperv_page(
+					    (unsigned long)hv_panic_page);
+					hv_panic_page = NULL;
+				}
 			} else
 				pr_err("Hyper-V: panic message page memory "
 					"allocation failed");
-- 
2.14.5