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| author | Jann Horn <jannh@google.com> | 2022-11-25 22:37:13 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-11-30 14:49:42 -0800 |
| commit | 2ba99c5e08812494bc57f319fb562f527d9bacd8 (patch) | |
| tree | 2a2cdaaa8a0bd83cc2e1a1feb93c6772a681a3cd /lib/show_mem.c | |
| parent | 8d3c106e19e8d251da31ff4cc7462e4565d65084 (diff) | |
| download | lwn-2ba99c5e08812494bc57f319fb562f527d9bacd8.tar.gz lwn-2ba99c5e08812494bc57f319fb562f527d9bacd8.zip | |
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>
Diffstat (limited to 'lib/show_mem.c')
0 files changed, 0 insertions, 0 deletions