FAILED: patch "[PATCH] x86/Hyper-V: Free hv_panic_page when fail to register kmsg" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Apr 21, 2020

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Stable branch Hyper-V/Azure core and drivers

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2020-04-21 17:19 UTC #0 lore raw

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7f11a2cc10a4ae3a70e2c73361f4a9a33503539b Mon Sep 17 00:00:00 2001
From: Tianyu Lan <[email protected]>
Date: Mon, 6 Apr 2020 08:53:27 -0700
Subject: [PATCH] x86/Hyper-V: Free hv_panic_page when fail to register kmsg
dump

If kmsg_dump_register() fails, hv_panic_page will not be used anywhere. So free and reset it.

Fixes 81b18bce48af ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")

Reviewed-by Michael Kelley <[email protected]>

Signed-off-by Tianyu Lan <[email protected]>

Link https://lore.kernel.org/r/[email protected] open here

Signed-off-by Wei Liu <[email protected]>

drivers/hv/vmbus_drv.c +5 -2

index 6478240d11ab..00a511f15926 100644
@@ -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");

@@ -1416,7 +1420,6 @@ static int vmbus_bus_init(void)
 	hv_remove_vmbus_irq();
 
 	bus_unregister(&hv_bus);
-	hv_free_hyperv_page((unsigned long)hv_panic_page);
 	unregister_sysctl_table(hv_ctl_table_hdr);
 	hv_ctl_table_hdr = NULL;
 	return ret;