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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2021-07-12 16:32:07 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-07-12 11:30:56 -0700 |
| commit | 79789db03fdd77510cfb35cb4b3bd52b6c50c901 (patch) | |
| tree | 44e6aba4c3735b180392437ef0d71f08a47337ee /mm/util.c | |
| parent | efdb6720b44b2f016d2a04b2c84e577e57ed84bd (diff) | |
| download | linux-79789db03fdd77510cfb35cb4b3bd52b6c50c901.tar.gz | |
mm: Make copy_huge_page() always available
Rewrite copy_huge_page() and move it into mm/util.c so it's always
available. Fixes an exposure of uninitialised memory on configurations
with HUGETLB and UFFD enabled and MIGRATION disabled.
Fixes: 8cc5fcbb5be8 ("mm, hugetlb: fix racy resv_huge_pages underflow on UFFDIO_COPY")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/util.c')
| -rw-r--r-- | mm/util.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/mm/util.c b/mm/util.c index 99c6cc77de9e..9043d03750a7 100644 --- a/mm/util.c +++ b/mm/util.c @@ -731,6 +731,16 @@ int __page_mapcount(struct page *page) } EXPORT_SYMBOL_GPL(__page_mapcount); +void copy_huge_page(struct page *dst, struct page *src) +{ + unsigned i, nr = compound_nr(src); + + for (i = 0; i < nr; i++) { + cond_resched(); + copy_highpage(nth_page(dst, i), nth_page(src, i)); + } +} + int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; int sysctl_overcommit_ratio __read_mostly = 50; unsigned long sysctl_overcommit_kbytes __read_mostly; |