Commit 8db0ec79 authored by Zi Yan's avatar Zi Yan Committed by Andrew Morton

fs: use nth_page() in place of direct struct page manipulation

When dealing with hugetlb pages, struct page is not guaranteed to be
contiguous on SPARSEMEM without VMEMMAP.  Use nth_page() to handle it
properly.

Without the fix, a wrong subpage might be checked for HWPoison, causing wrong
number of bytes of a page copied to user space. No bug is reported. The fix
comes from code inspection.

Link: https://lkml.kernel.org/r/20230913201248.452081-5-zi.yan@sent.com
Fixes: 38c1ddbd ("hugetlbfs: improve read HWPOISON hugepage")
Signed-off-by: default avatarZi Yan <ziy@nvidia.com>
Reviewed-by: default avatarMuchun Song <songmuchun@bytedance.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 1640a0ef
...@@ -295,7 +295,7 @@ static size_t adjust_range_hwpoison(struct page *page, size_t offset, size_t byt ...@@ -295,7 +295,7 @@ static size_t adjust_range_hwpoison(struct page *page, size_t offset, size_t byt
size_t res = 0; size_t res = 0;
/* First subpage to start the loop. */ /* First subpage to start the loop. */
page += offset / PAGE_SIZE; page = nth_page(page, offset / PAGE_SIZE);
offset %= PAGE_SIZE; offset %= PAGE_SIZE;
while (1) { while (1) {
if (is_raw_hwpoison_page_in_hugepage(page)) if (is_raw_hwpoison_page_in_hugepage(page))
...@@ -309,7 +309,7 @@ static size_t adjust_range_hwpoison(struct page *page, size_t offset, size_t byt ...@@ -309,7 +309,7 @@ static size_t adjust_range_hwpoison(struct page *page, size_t offset, size_t byt
break; break;
offset += n; offset += n;
if (offset == PAGE_SIZE) { if (offset == PAGE_SIZE) {
page++; page = nth_page(page, 1);
offset = 0; offset = 0;
} }
} }
......
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