2019-04-11 11:12:07

by David Hildenbrand

Subject: [PATCH v2] mm/memory_hotplug: Drop memory device reference after find_memory_block()

Right now we are using find_memory_block() to get the node id for the
pfn range to online. We are missing to drop a reference to the memory
block device. While the device still gets unregistered via
device_unregister(), resulting in no user visible problem, the device is
never released via device_release(), resulting in a memory leak. Fix
that by properly using a put_device().

Fixes: d0dc12e86b31 ("mm/memory_hotplug: optimize memory hotplug")
Cc: Andrew Morton <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Pavel Tatashin <[email protected]>
Cc: Wei Yang <[email protected]>
Cc: Qian Cai <[email protected]>
Cc: Arun KS <[email protected]>
Cc: Mathieu Malaterre <[email protected]>
Reviewed-by: Oscar Salvador <[email protected]>
Reviewed-by: Wei Yang <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Signed-off-by: David Hildenbrand <[email protected]>
---
mm/memory_hotplug.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 5eb4a4c7c21b..328878b6799d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -854,6 +854,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
*/
mem = find_memory_block(__pfn_to_section(pfn));
nid = mem->nid;
+ put_device(&mem->dev);

/* associate pfn range with the zone */
zone = move_pfn_range(online_type, nid, pfn, nr_pages);
--
2.20.1

2019-04-11 11:21:28

by Pankaj Gupta

Subject: Re: [PATCH v2] mm/memory_hotplug: Drop memory device reference after find_memory_block()

> Right now we are using find_memory_block() to get the node id for the
> pfn range to online. We are missing to drop a reference to the memory
> block device. While the device still gets unregistered via
> device_unregister(), resulting in no user visible problem, the device is
> never released via device_release(), resulting in a memory leak. Fix
> that by properly using a put_device().
>
> Fixes: d0dc12e86b31 ("mm/memory_hotplug: optimize memory hotplug")
> Cc: Andrew Morton <[email protected]>
> Cc: Oscar Salvador <[email protected]>
> Cc: Michal Hocko <[email protected]>
> Cc: David Hildenbrand <[email protected]>
> Cc: Pavel Tatashin <[email protected]>
> Cc: Wei Yang <[email protected]>
> Cc: Qian Cai <[email protected]>
> Cc: Arun KS <[email protected]>
> Cc: Mathieu Malaterre <[email protected]>
> Reviewed-by: Oscar Salvador <[email protected]>
> Reviewed-by: Wei Yang <[email protected]>
> Acked-by: Michal Hocko <[email protected]>
> Signed-off-by: David Hildenbrand <[email protected]>
> ---
> mm/memory_hotplug.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 5eb4a4c7c21b..328878b6799d 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -854,6 +854,7 @@ int __ref online_pages(unsigned long pfn, unsigned long
> nr_pages, int online_typ
> */
> mem = find_memory_block(__pfn_to_section(pfn));
> nid = mem->nid;
> + put_device(&mem->dev);
>
> /* associate pfn range with the zone */
> zone = move_pfn_range(online_type, nid, pfn, nr_pages);
> --
> 2.20.1

Good catch it is.

Acked-by: Pankaj Gupta <[email protected]>

>
>