On 11/7/18 4:14 AM, Michael Ellerman wrote:
> frowand.list@xxxxxxxxx writes:
>
>> From: Frank Rowand <frank.rowand@xxxxxxxx>
>>
>> There is a matching of_node_put() in __of_detach_node_sysfs()
>>
>> Remove misleading comment from function header comment for
>> of_detach_node().
>>
>> This patch may result in memory leaks from code that directly calls
>> the dynamic node add and delete functions directly instead of
>> using changesets.
>>
>> Tested-by: Alan Tull <atull@xxxxxxxxxx>
>> Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxx>
>
> This seems sensible to me. I guess we could argue about whether the
> sysfs code needs its own reference, but it certainly doesn't hurt that
> it does, as long as it's handled symmetrically - which it is now.
>
> Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> (powerpc)
>
>> ---
>>
>> This patch should result in powerpc systems that dynamically
>> allocate a node, then later deallocate the node to have a
>> memory leak when the node is deallocated.
>>
>> The next patch in the series will fix the leak.
>
> I think this should go in the changelog, it's useful information that we
> don't want to lose track of once this is applied.
Will do.
-Frank
>
> Either that or we actually squash the two patches together when applying
> to avoid the bisection break.
>
> cheers
>
>> drivers/of/dynamic.c | 3 ---
>> drivers/of/kobj.c | 4 +++-
>> 2 files changed, 3 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
>> index 12c3f9a15e94..146681540487 100644
>> --- a/drivers/of/dynamic.c
>> +++ b/drivers/of/dynamic.c
>> @@ -272,9 +272,6 @@ void __of_detach_node(struct device_node *np)
>>
>> /**
>> * of_detach_node() - "Unplug" a node from the device tree.
>> - *
>> - * The caller must hold a reference to the node. The memory associated with
>> - * the node is not freed until its refcount goes to zero.
>> */
>> int of_detach_node(struct device_node *np)
>> {
>> diff --git a/drivers/of/kobj.c b/drivers/of/kobj.c
>> index 7a0a18980b98..c72eef988041 100644
>> --- a/drivers/of/kobj.c
>> +++ b/drivers/of/kobj.c
>> @@ -133,6 +133,9 @@ int __of_attach_node_sysfs(struct device_node *np)
>> }
>> if (!name)
>> return -ENOMEM;
>> +
>> + of_node_get(np);
>> +
>> rc = kobject_add(&np->kobj, parent, "%s", name);
>> kfree(name);
>> if (rc)
>> @@ -159,6 +162,5 @@ void __of_detach_node_sysfs(struct device_node *np)
>> kobject_del(&np->kobj);
>> }
>>
>> - /* finally remove the kobj_init ref */
>> of_node_put(np);
>> }
>> --
>> Frank Rowand <frank.rowand@xxxxxxxx>
>
