On Tue 23-06-20 17:42:58, Wei Yang wrote:
> For early sections, we assumes its memmap will never be partially
> removed. But current behavior breaks this.
>
> Let's correct it.
>
> Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug")
> Signed-off-by: Wei Yang <richard.weiy...@linux.alibaba.com>
Can a user trigger this or is this a theoretical bug?
> ---
> mm/sparse.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/mm/sparse.c b/mm/sparse.c
> index b2b9a3e34696..1a0069f492f5 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -825,10 +825,10 @@ static void section_deactivate(unsigned long pfn,
> unsigned long nr_pages,
> ms->section_mem_map &= ~SECTION_HAS_MEM_MAP;
> }
>
> - if (section_is_early && memmap)
> - free_map_bootmem(memmap);
> - else
> + if (!section_is_early)
This begs a comment.
> depopulate_section_memmap(pfn, nr_pages, altmap);
> + else if (memmap)
> + free_map_bootmem(memmap);
>
> if (empty)
> ms->section_mem_map = (unsigned long)NULL;
> --
> 2.20.1 (Apple Git-117)
>
--
Michal Hocko
SUSE Labs
