The patch titled
Subject: mm: fix false-positive WARN_ON() in truncate/invalidate for hugetlb
has been added to the -mm tree. Its filename is
mm-fix-false-positive-warn_on-in-truncate-invalidate-for-hugetlb.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-fix-false-positive-warn_on-in-truncate-invalidate-for-hugetlb.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-false-positive-warn_on-in-truncate-invalidate-for-hugetlb.patch
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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: mm: fix false-positive WARN_ON() in truncate/invalidate for hugetlb
Hugetlb pages have ->index in size of the huge pages (PMD_SIZE or
PUD_SIZE), not in PAGE_SIZE as other types of pages. This means we cannot
user page_to_pgoff() to check whether we've got the right page for the
radix-tree index.
Let's introduce page_to_index() which would return radix-tree index for
given page.
We will be able to get rid of this once hugetlb will be switched to
multi-order entries.
Fixes: fc127da085c2 ("truncate: handle file thp")
Link: http://lkml.kernel.org/r/20161123093053.mjbnvn5zwxw5e6lk@xxxxxxxxxxxxxxxxxx
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reported-by: Doug Nelson <doug.nelson@xxxxxxxxx>
Tested-by: Doug Nelson <doug.nelson@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [4.8+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/pagemap.h | 21 +++++++++++++++------
mm/truncate.c | 8 ++++----
2 files changed, 19 insertions(+), 10 deletions(-)
diff -puN include/linux/pagemap.h~mm-fix-false-positive-warn_on-in-truncate-invalidate-for-hugetlb include/linux/pagemap.h
--- a/include/linux/pagemap.h~mm-fix-false-positive-warn_on-in-truncate-invalidate-for-hugetlb
+++ a/include/linux/pagemap.h
@@ -374,16 +374,13 @@ static inline struct page *read_mapping_
}
/*
- * Get the offset in PAGE_SIZE.
- * (TODO: hugepage should have ->index in PAGE_SIZE)
+ * Get index of the page with in radix-tree
+ * (TODO: remove once hugetlb pages will have ->index in PAGE_SIZE)
*/
-static inline pgoff_t page_to_pgoff(struct page *page)
+static inline pgoff_t page_to_index(struct page *page)
{
pgoff_t pgoff;
- if (unlikely(PageHeadHuge(page)))
- return page->index << compound_order(page);
-
if (likely(!PageTransTail(page)))
return page->index;
@@ -397,6 +394,18 @@ static inline pgoff_t page_to_pgoff(stru
}
/*
+ * Get the offset in PAGE_SIZE.
+ * (TODO: hugepage should have ->index in PAGE_SIZE)
+ */
+static inline pgoff_t page_to_pgoff(struct page *page)
+{
+ if (unlikely(PageHeadHuge(page)))
+ return page->index << compound_order(page);
+
+ return page_to_index(page);
+}
+
+/*
* Return byte-offset into filesystem object for page.
*/
static inline loff_t page_offset(struct page *page)
diff -puN mm/truncate.c~mm-fix-false-positive-warn_on-in-truncate-invalidate-for-hugetlb mm/truncate.c
--- a/mm/truncate.c~mm-fix-false-positive-warn_on-in-truncate-invalidate-for-hugetlb
+++ a/mm/truncate.c
@@ -283,7 +283,7 @@ void truncate_inode_pages_range(struct a
if (!trylock_page(page))
continue;
- WARN_ON(page_to_pgoff(page) != index);
+ WARN_ON(page_to_index(page) != index);
if (PageWriteback(page)) {
unlock_page(page);
continue;
@@ -371,7 +371,7 @@ void truncate_inode_pages_range(struct a
}
lock_page(page);
- WARN_ON(page_to_pgoff(page) != index);
+ WARN_ON(page_to_index(page) != index);
wait_on_page_writeback(page);
truncate_inode_page(mapping, page);
unlock_page(page);
@@ -492,7 +492,7 @@ unsigned long invalidate_mapping_pages(s
if (!trylock_page(page))
continue;
- WARN_ON(page_to_pgoff(page) != index);
+ WARN_ON(page_to_index(page) != index);
/* Middle of THP: skip */
if (PageTransTail(page)) {
@@ -612,7 +612,7 @@ int invalidate_inode_pages2_range(struct
}
lock_page(page);
- WARN_ON(page_to_pgoff(page) != index);
+ WARN_ON(page_to_index(page) != index);
if (page->mapping != mapping) {
unlock_page(page);
continue;
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
mm-bug-in-munlock_vma_pages_range.patch
mm-fix-false-positive-warn_on-in-truncate-invalidate-for-hugetlb.patch
filemap-add-comment-for-confusing-logic-in-page_cache_tree_insert.patch
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