The patch titled
Subject: mm: gup: fix potential pgmap refcnt leak in __gup_device_huge()
has been added to the -mm tree. Its filename is
mm-gup-fix-potential-pgmap-refcnt-leak-in-__gup_device_huge.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-gup-fix-potential-pgmap-refcnt-leak-in-__gup_device_huge.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-gup-fix-potential-pgmap-refcnt-leak-in-__gup_device_huge.patch
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------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm: gup: fix potential pgmap refcnt leak in __gup_device_huge()
When failed to try_grab_page, put_dev_pagemap() is missed. So pgmap
refcnt will leak in this case. Also we remove the check for pgmap against
NULL as it's also checked inside the put_dev_pagemap().
Link: https://lkml.kernel.org/r/20210807093620.21347-5-linmiaohe@xxxxxxxxxx
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Fixes: 3faa52c03f44 ("mm/gup: track FOLL_PIN pages")
Cc: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/gup.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/gup.c~mm-gup-fix-potential-pgmap-refcnt-leak-in-__gup_device_huge
+++ a/mm/gup.c
@@ -2253,14 +2253,14 @@ static int __gup_device_huge(unsigned lo
pages[*nr] = page;
if (unlikely(!try_grab_page(page, flags))) {
undo_dev_pagemap(nr, nr_start, flags, pages);
+ put_dev_pagemap(pgmap);
return 0;
}
(*nr)++;
pfn++;
} while (addr += PAGE_SIZE, addr != end);
- if (pgmap)
- put_dev_pagemap(pgmap);
+ put_dev_pagemap(pgmap);
return 1;
}
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-gup-remove-set-but-unused-local-variable-major.patch
mm-gup-remove-unneed-local-variable-orig_refs.patch
mm-gup-remove-useless-bug_on-in-__get_user_pages.patch
mm-gup-fix-potential-pgmap-refcnt-leak-in-__gup_device_huge.patch
mm-gup-use-helper-page_aligned-in-populate_vma_page_range.patch
mm-vmscan-remove-the-pagedirty-check-after-madv_free-pages-are-page_ref_freezed.patch
mm-vmscan-remove-misleading-setting-to-sc-priority.patch
mm-vmscan-remove-unneeded-return-value-of-kswapd_run.patch
mm-vmscan-add-else-to-remove-check_pending-label.patch
mm-vmstat-correct-some-wrong-comments.patch
mm-vmstat-simplify-the-array-size-calculation.patch
mm-vmstat-remove-unneeded-return-value.patch
mm-zsmallocc-close-race-window-between-zs_pool_dec_isolated-and-zs_unregister_migration.patch
mm-zsmallocc-combine-two-atomic-ops-in-zs_pool_dec_isolated.patch
