The of_find_compatible_node() function returns a node pointer with
refcount incremented, We should use of_node_put() on it when done
Add the missing of_node_put() to release the refcount.
Fixes: 9b08aaa3199a ("ARM: XEN: Move xen_early_init() before efi_init()")
Signed-off-by: Miaoqian Lin <[email protected]>
---
arch/arm/xen/enlighten.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index ec5b082f3de6..262f45f686b6 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -424,6 +424,7 @@ static void __init xen_dt_guest_init(void)
if (of_address_to_resource(xen_node, GRANT_TABLE_INDEX, &res)) {
pr_err("Xen grant table region is not found\n");
+ of_node_put(xen_node);
return;
}
xen_grant_frames = res.start;
--
2.17.1
On Wed, 9 Mar 2022, Miaoqian Lin wrote:
> The of_find_compatible_node() function returns a node pointer with
> refcount incremented, We should use of_node_put() on it when done
> Add the missing of_node_put() to release the refcount.
>
> Fixes: 9b08aaa3199a ("ARM: XEN: Move xen_early_init() before efi_init()")
> Signed-off-by: Miaoqian Lin <[email protected]>
Thanks for the patch!
> ---
> arch/arm/xen/enlighten.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index ec5b082f3de6..262f45f686b6 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -424,6 +424,7 @@ static void __init xen_dt_guest_init(void)
>
> if (of_address_to_resource(xen_node, GRANT_TABLE_INDEX, &res)) {
> pr_err("Xen grant table region is not found\n");
> + of_node_put(xen_node);
> return;
> }
This is adding a call to of_node_put on the error path. Shouldn't it
be called also in the non-error path?
Also, there is another instance of of_address_to_resource being called
in this file (in arch_xen_unpopulated_init), does it make sense to call
of_node_put there too?
Hi,
On Fri, Mar 11, 2022 at 06:01:11PM -0800, Stefano Stabellini wrote:
> On Wed, 9 Mar 2022, Miaoqian Lin wrote:
> > The of_find_compatible_node() function returns a node pointer with
> > refcount incremented, We should use of_node_put() on it when done
> > Add the missing of_node_put() to release the refcount.
> >
> > Fixes: 9b08aaa3199a ("ARM: XEN: Move xen_early_init() before efi_init()")
> > Signed-off-by: Miaoqian Lin <[email protected]>
>
> Thanks for the patch!
>
>
> > ---
> > arch/arm/xen/enlighten.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> > index ec5b082f3de6..262f45f686b6 100644
> > --- a/arch/arm/xen/enlighten.c
> > +++ b/arch/arm/xen/enlighten.c
> > @@ -424,6 +424,7 @@ static void __init xen_dt_guest_init(void)
> >
> > if (of_address_to_resource(xen_node, GRANT_TABLE_INDEX, &res)) {
> > pr_err("Xen grant table region is not found\n");
> > + of_node_put(xen_node);
> > return;
> > }
>
> This is adding a call to of_node_put on the error path. Shouldn't it
> be called also in the non-error path?
You're right. It should be called also in the non-error path.
I made a mistake.
> Also, there is another instance of of_address_to_resource being called
> in this file (in arch_xen_unpopulated_init), does it make sense to call
> of_node_put there too?
I think so, becase device node pointer np is a local variable.
So the reference it taken should be released in the scope.
I look into the whole codebase for this kind of usage pattern
($ret=of_find_compatible_node();of_address_to_resource($ret,_,_),
$ret is a local variable), Most of them call of_node_put() when done.
And document of of_find_compatible_node() also mentions
> Return: A node pointer with refcount incremented, use
> of_node_put() on it when done.
But I am not sure, Since I am unfamiliar with other code logic.
It better if the developers could double check. I found some
similar cases in arch/arm.
The of_find_compatible_node() function returns a node pointer with
refcount incremented, We should use of_node_put() on it when done
Add the missing of_node_put() to release the refcount.
Fixes: 9b08aaa3199a ("ARM: XEN: Move xen_early_init() before efi_init()")
Fixes: b2371587fe0c ("arm/xen: Read extended regions from DT and init Xen resource")
Signed-off-by: Miaoqian Lin <[email protected]>
---
changes in v2:
- call of_node_put in non-error path in xen_dt_guest_init
- fix same refcount leak error in arch_xen_unpopulated_init
---
arch/arm/xen/enlighten.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index ec5b082f3de6..07eb69f9e7df 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -337,12 +337,15 @@ int __init arch_xen_unpopulated_init(struct resource **res)
if (!nr_reg) {
pr_err("No extended regions are found\n");
+ of_node_put(np);
return -EINVAL;
}
regs = kcalloc(nr_reg, sizeof(*regs), GFP_KERNEL);
- if (!regs)
+ if (!regs) {
+ of_node_put(np);
return -ENOMEM;
+ }
/*
* Create resource from extended regions provided by the hypervisor to be
@@ -403,8 +406,8 @@ int __init arch_xen_unpopulated_init(struct resource **res)
*res = &xen_resource;
err:
+ of_node_put(np);
kfree(regs);
-
return rc;
}
#endif
@@ -424,8 +427,10 @@ static void __init xen_dt_guest_init(void)
if (of_address_to_resource(xen_node, GRANT_TABLE_INDEX, &res)) {
pr_err("Xen grant table region is not found\n");
+ of_node_put(xen_node);
return;
}
+ of_node_put(xen_node);
xen_grant_frames = res.start;
}
--
2.17.1
On Wed, 20 Apr 2022, Miaoqian Lin wrote:
> The of_find_compatible_node() function returns a node pointer with
> refcount incremented, We should use of_node_put() on it when done
> Add the missing of_node_put() to release the refcount.
>
> Fixes: 9b08aaa3199a ("ARM: XEN: Move xen_early_init() before efi_init()")
> Fixes: b2371587fe0c ("arm/xen: Read extended regions from DT and init Xen resource")
> Signed-off-by: Miaoqian Lin <[email protected]>
Reviewed-by: Stefano Stabellini <[email protected]>
Juergen, Boris,
I applied the patch to for-linus-5.18
> ---
> changes in v2:
> - call of_node_put in non-error path in xen_dt_guest_init
> - fix same refcount leak error in arch_xen_unpopulated_init
> ---
> arch/arm/xen/enlighten.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index ec5b082f3de6..07eb69f9e7df 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -337,12 +337,15 @@ int __init arch_xen_unpopulated_init(struct resource **res)
>
> if (!nr_reg) {
> pr_err("No extended regions are found\n");
> + of_node_put(np);
> return -EINVAL;
> }
>
> regs = kcalloc(nr_reg, sizeof(*regs), GFP_KERNEL);
> - if (!regs)
> + if (!regs) {
> + of_node_put(np);
> return -ENOMEM;
> + }
>
> /*
> * Create resource from extended regions provided by the hypervisor to be
> @@ -403,8 +406,8 @@ int __init arch_xen_unpopulated_init(struct resource **res)
> *res = &xen_resource;
>
> err:
> + of_node_put(np);
> kfree(regs);
> -
> return rc;
> }
> #endif
> @@ -424,8 +427,10 @@ static void __init xen_dt_guest_init(void)
>
> if (of_address_to_resource(xen_node, GRANT_TABLE_INDEX, &res)) {
> pr_err("Xen grant table region is not found\n");
> + of_node_put(xen_node);
> return;
> }
> + of_node_put(xen_node);
> xen_grant_frames = res.start;
> }
>
> --
> 2.17.1
>