arch/arm/xen/enlighten.c | 1 + 1 file changed, 1 insertion(+)
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 <linmq006@gmail.com>
---
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 <linmq006@gmail.com> 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 <linmq006@gmail.com> > > 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 <linmq006@gmail.com>
---
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 <linmq006@gmail.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> 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 >
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