Jann Horn 2ba99c5e08 mm/khugepaged: fix GUP-fast interaction by sending IPI
Since commit 70cbc3cc78a99 ("mm: gup: fix the fast GUP race against THP
collapse"), the lockless_pages_from_mm() fastpath rechecks the pmd_t to
ensure that the page table was not removed by khugepaged in between.

However, lockless_pages_from_mm() still requires that the page table is
not concurrently freed.  Fix it by sending IPIs (if the architecture uses
semi-RCU-style page table freeing) before freeing/reusing page tables.

Link: https://lkml.kernel.org/r/20221129154730.2274278-2-jannh@google.com
Link: https://lkml.kernel.org/r/20221128180252.1684965-2-jannh@google.com
Link: https://lkml.kernel.org/r/20221125213714.4115729-2-jannh@google.com
Fixes: ba76149f47d8 ("thp: khugepaged")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30 14:49:42 -08:00
..
2022-11-22 18:50:44 -08:00
2022-09-26 19:46:26 -07:00
2022-10-03 14:02:53 -07:00
2022-09-26 19:46:16 -07:00
2022-10-03 14:02:53 -07:00
2022-03-23 18:03:08 -07:00
2022-10-03 14:03:04 -07:00
2022-06-16 19:48:30 -07:00
2022-05-13 07:20:09 -07:00
2022-09-26 19:46:09 -07:00
2022-10-03 14:02:43 -07:00
2022-09-26 19:46:09 -07:00
2022-09-26 19:46:28 -07:00
2022-09-26 19:46:26 -07:00
2022-10-03 14:02:45 -07:00
2022-10-03 14:02:51 -07:00
2022-10-03 14:02:45 -07:00
2022-01-15 16:30:31 +02:00