[PATCH stable 5.10 0/1] Fix memleak during hotremove memory

[Wupeng Ma <mawupeng1@huawei.com>]

From: Ma Wupeng <mawupeng1@huawei.com>

Hi maintainers:

Our test find a memleak in init_memory_block, it is clear that mem is never
been released due to wrong refcount. Commit 08b3acd7a68f ("mm/memory_hotplug:
Introduce offline_and_remove_memory()") failed to dec refcount after
find_memory_block which fail to dec refcount to zero in remove memory
causing the leak.

Commit 8dc4bb58a146 ("mm/memory_hotplug: extend offline_and_remove_memory()
to handle more than one memory block") introduce walk_memory_blocks to
replace find_memory_block which dec refcount by calling put_device after
find_memory_block_by_id. In the way, the memleak is fixed.

Here is the simplified calltrace:

  kmem_cache_alloc_trace+0x664/0xed0
  init_memory_block+0x8c/0x170
  create_memory_block_devices+0xa4/0x150
  add_memory_resource+0x188/0x530
  __add_memory+0x78/0x104
  add_memory+0x6c/0xb0

David Hildenbrand (1):
  mm/memory_hotplug: extend offline_and_remove_memory() to handle more
    than one memory block

 mm/memory_hotplug.c | 105 +++++++++++++++++++++++++++++++++++++-------
 1 file changed, 89 insertions(+), 16 deletions(-)

-- 
2.25.1