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

[Tianyu Lan]

Hi Wei:
	Thanks for your review.

On 3/18/2020 1:36 AM, Wei Liu wrote:
> On Tue, Mar 17, 2020 at 06:25:21AM -0700, ltykernel@xxxxxxxxx wrote:
> > 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;
> > +				}
>
> While this modification looks correct to me, there is a call to free
> hv_panic_page in the err_alloc path. That makes the error handling a bit
> confusing here.
>
> I think you can just remove that function call in err_alloc path.

OK. Will update in the next version.

> Wei.
>
> >   			} else
> >   				pr_err("Hyper-V: panic message page memory "
> >   					"allocation failed");
> > --
> > 2.14.5