On 16.12.24 19:33, jane.chu@xxxxxxxxxx wrote:
On 12/14/2024 2:44 AM, Liu Shixin wrote:
The folio refcount may be increased unexpectly through try_get_folio() by
caller such as split_huge_pages. In huge_pmd_unshare(), we use refcount to
check whether a pmd page table is shared. The check is incorrect if the
refcount is increased by the above caller, and this can cause the page
table leaked:
hugetlb and THP don't overlap, right? how does split_huge_pages() end
up messing up huge_pmd_share() ?
Am I missing something?
If first grabs a reference to then check if it's a THP. So we can end up
grabbing anything temporarily.
In general, we'll have to be smarter about what we try grabbing, but
handling races for now is tricky.
--
Cheers,
David / dhildenb
