diff options
| author | Hugh Dickins <hughd@google.com> | 2021-04-23 14:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-04-23 14:42:39 -0700 |
| commit | 2d11e738151d6cd321dd944cefe9c941ea00086c (patch) | |
| tree | 7d8232a0980f20ba74fb57c3879ac71be65e111d | |
| parent | 2896900e22f8212606a1837d89a6bbce314ceeda (diff) | |
mm/filemap: fix find_lock_entries hang on 32-bit THP
No problem on 64-bit, or without huge pages, but xfstests generic/308
hung uninterruptibly on 32-bit huge tmpfs.
Since commit 0cc3b0ec23ce ("Clarify (and fix) in 4.13 MAX_LFS_FILESIZE
macros"), MAX_LFS_FILESIZE is only a PAGE_SIZE away from wrapping 32-bit
xa_index to 0, so the new find_lock_entries() has to be extra careful
when handling a THP.
Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2104211735430.3299@eggly.anvils
Fixes: 5c211ba29deb ("mm: add and use find_lock_entries")
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/filemap.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 43700480d897..bcf64e92ffb0 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1969,8 +1969,14 @@ unlock: put: put_page(page); next: - if (!xa_is_value(page) && PageTransHuge(page)) - xas_set(&xas, page->index + thp_nr_pages(page)); + if (!xa_is_value(page) && PageTransHuge(page)) { + unsigned int nr_pages = thp_nr_pages(page); + + /* Final THP may cross MAX_LFS_FILESIZE on 32-bit */ + xas_set(&xas, page->index + nr_pages); + if (xas.xa_index < nr_pages) + break; + } } rcu_read_unlock(); |