* Re: [PATCH 1/1] xen: xenbus: set error code on failure
[not found] <1480762166-4883-1-git-send-email-bianpan2016@163.com>
@ 2016-12-05 6:30 ` Juergen Gross
[not found] ` <dd8548fe-7933-c26c-38ca-895599e5c144@suse.com>
1 sibling, 0 replies; 3+ messages in thread
From: Juergen Gross @ 2016-12-05 6:30 UTC (permalink / raw)
To: Pan Bian, Boris Ostrovsky, David Vrabel, xen-devel; +Cc: linux-kernel
On 03/12/16 11:49, Pan Bian wrote:
> In function xenstored_local_init(), the value of return variable err
> should be negative on errors. But the value of err keeps 0 even if the
> call to get_zeroed_page() returns a NULL pointer. This patch assigns
> "-ENOMEM" to err on the error branch.
>
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188721
>
> Signed-off-by: Pan Bian <bianpan2016@163.com>
> ---
> drivers/xen/xenbus/xenbus_probe.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
> index 33a31cf..f87d047 100644
> --- a/drivers/xen/xenbus/xenbus_probe.c
> +++ b/drivers/xen/xenbus/xenbus_probe.c
> @@ -708,8 +708,10 @@ static int __init xenstored_local_init(void)
>
> /* Allocate Xenstore page */
> page = get_zeroed_page(GFP_KERNEL);
> - if (!page)
> + if (!page) {
> + err = -ENOMEM;
> goto out_err;
> + }
>
> xen_store_gfn = xen_start_info->store_mfn = virt_to_gfn((void *)page);
Why don't you preset err to -ENOMEM instead? Initializing it to 0
is kind of pointless.
Ans while at it: preinitializing page isn't needed, too, and in the
error path testing page for being non-zero isn't neede either
(free_page() will do the right thing in case the parameter is 0).
Juergen
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^ permalink raw reply [flat|nested] 3+ messages in thread[parent not found: <dd8548fe-7933-c26c-38ca-895599e5c144@suse.com>]
* Re: [PATCH 1/1] xen: xenbus: set error code on failure
[not found] ` <dd8548fe-7933-c26c-38ca-895599e5c144@suse.com>
@ 2016-12-05 7:50 ` Pan Bian
0 siblings, 0 replies; 3+ messages in thread
From: Pan Bian @ 2016-12-05 7:50 UTC (permalink / raw)
To: Juergen Gross, Boris Ostrovsky, David Vrabel, xen-devel
Cc: PanBian, linux-kernel
From: PanBian <bianpan2016@163.com>
On Mon, Dec 05, 2016 at 07:30:49AM +0100, Juergen Gross wrote:
> On 03/12/16 11:49, Pan Bian wrote:
> > In function xenstored_local_init(), the value of return variable err
> > should be negative on errors. But the value of err keeps 0 even if the
> > call to get_zeroed_page() returns a NULL pointer. This patch assigns
> > "-ENOMEM" to err on the error branch.
> >
> > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188721
> >
> > Signed-off-by: Pan Bian <bianpan2016@163.com>
> > ---
> > drivers/xen/xenbus/xenbus_probe.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
> > index 33a31cf..f87d047 100644
> > --- a/drivers/xen/xenbus/xenbus_probe.c
> > +++ b/drivers/xen/xenbus/xenbus_probe.c
> > @@ -708,8 +708,10 @@ static int __init xenstored_local_init(void)
> >
> > /* Allocate Xenstore page */
> > page = get_zeroed_page(GFP_KERNEL);
> > - if (!page)
> > + if (!page) {
> > + err = -ENOMEM;
> > goto out_err;
> > + }
> >
> > xen_store_gfn = xen_start_info->store_mfn = virt_to_gfn((void *)page);
>
> Why don't you preset err to -ENOMEM instead? Initializing it to 0
> is kind of pointless.
I think presetting and setting on demand are both effective to fix
this bug. Nevertheless, I will resubmit a second version if you
insist.
>
> Ans while at it: preinitializing page isn't needed, too, and in the
> error path testing page for being non-zero isn't neede either
> (free_page() will do the right thing in case the parameter is 0).
>
>
> Juergen
>
Thanks!
Best regards,
Pan
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^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 1/1] xen: xenbus: set error code on failure
@ 2016-12-03 10:49 Pan Bian
0 siblings, 0 replies; 3+ messages in thread
From: Pan Bian @ 2016-12-03 10:49 UTC (permalink / raw)
To: Boris Ostrovsky, David Vrabel, Juergen Gross, xen-devel
Cc: Pan Bian, linux-kernel
In function xenstored_local_init(), the value of return variable err
should be negative on errors. But the value of err keeps 0 even if the
call to get_zeroed_page() returns a NULL pointer. This patch assigns
"-ENOMEM" to err on the error branch.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188721
Signed-off-by: Pan Bian <bianpan2016@163.com>
---
drivers/xen/xenbus/xenbus_probe.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 33a31cf..f87d047 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -708,8 +708,10 @@ static int __init xenstored_local_init(void)
/* Allocate Xenstore page */
page = get_zeroed_page(GFP_KERNEL);
- if (!page)
+ if (!page) {
+ err = -ENOMEM;
goto out_err;
+ }
xen_store_gfn = xen_start_info->store_mfn = virt_to_gfn((void *)page);
--
1.9.1
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2016-12-05 6:30 ` [PATCH 1/1] xen: xenbus: set error code on failure Juergen Gross
[not found] ` <dd8548fe-7933-c26c-38ca-895599e5c144@suse.com>
2016-12-05 7:50 ` Pan Bian
2016-12-03 10:49 Pan Bian
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