linux-kernel - RE: [PATCH 2/4] x86/Hyper-V: Free hv_panic

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Message-ID: <MW2PR2101MB105297BB206C91C1CBF1477DD7F40@MW2PR2101MB1052.namprd21.prod.outlook.com>
Date:   Thu, 19 Mar 2020 00:38:07 +0000
From:   Michael Kelley <mikelley@...rosoft.com>
To:     "ltykernel@...il.com" <ltykernel@...il.com>,
        KY Srinivasan <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Wei Liu <liuwe@...rosoft.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "bp@...en8.de" <bp@...en8.de>, "hpa@...or.com" <hpa@...or.com>,
        "x86@...nel.org" <x86@...nel.org>
CC:     Tianyu Lan <Tianyu.Lan@...rosoft.com>,
        "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        vkuznets <vkuznets@...hat.com>
Subject: RE: [PATCH 2/4] x86/Hyper-V: Free hv_panic_page when fail to register
 kmsg dump

From: ltykernel@...il.com <ltykernel@...il.com> Sent: Tuesday, March 17, 2020 6:25 AM
> 
> If fail to register kmsg dump on Hyper-V platform, hv_panic_page
> will not be used anywhere. So free and reset it.

Slight commit message wording cleanup:

If kmsg_dump_register() fails, 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