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

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Message-Id: <20200317132523.1508-3-Tianyu.Lan@microsoft.com>
Date:   Tue, 17 Mar 2020 06:25:21 -0700
From:   ltykernel@...il.com
To:     kys@...rosoft.com, haiyangz@...rosoft.com, sthemmin@...rosoft.com,
        liuwe@...rosoft.com, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, hpa@...or.com, x86@...nel.org,
        michael.h.kelley@...rosoft.com
Cc:     Tianyu Lan <Tianyu.Lan@...rosoft.com>,
        linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org,
        vkuznets@...hat.com
Subject: [PATCH 2/4] x86/Hyper-V: Free hv_panic_page when fail to register kmsg dump

From: Tianyu Lan <Tianyu.Lan@...rosoft.com>

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@...rosoft.com>
---
 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