The patch titled Subject: memfd: fix shmem huge page failed to set F_SEAL_WRITE attribute problem has been added to the -mm tree. Its filename is fix-shmem-huge-page-failed-to-set-f_seal_write-attribute-problem.patch
This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/fix-shmem-huge-page-failed-to-set-... and later at https://ozlabs.org/~akpm/mmotm/broken-out/fix-shmem-huge-page-failed-to-set-...
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------------------------------------------------------ From: wangyong wang.yong12@zte.com.cn Subject: memfd: fix shmem huge page failed to set F_SEAL_WRITE attribute problem
After enabling tmpfs filesystem to support transparent hugepage with the following command:
echo always > /sys/kernel/mm/transparent_hugepage/shmem_enabled
The docker program adds F_SEAL_WRITE through the following command which will prompt EBUSY.
fcntl(5, F_ADD_SEALS, F_SEAL_WRITE)=-1.
It is found that in memfd_wait_for_pins function, the page_count of hugepage is 512 and page_mapcount is 0, which does not meet the conditions:
page_count(page) - page_mapcount(page) != 1.
But the page is not busy at this time, therefore, the page_order of hugepage should be taken into account in the calculation.
Link: https://lkml.kernel.org/r/20220215073743.1769979-1-cgel.zte@gmail.com Signed-off-by: wangyong wang.yong12@zte.com.cn Reported-by: Zeal Robot zealci@zte.com.cn Cc: Hugh Dickins hughd@google.com Cc: Mike Kravetz mike.kravetz@oracle.com Cc: Kirill A. Shutemov kirill@shutemov.name Cc: Song Liu songliubraving@fb.com Cc: Yang Yang yang.yang29@zte.com.cn Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/memfd.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
--- a/mm/memfd.c~fix-shmem-huge-page-failed-to-set-f_seal_write-attribute-problem +++ a/mm/memfd.c @@ -31,6 +31,7 @@ static void memfd_tag_pins(struct xa_state *xas) { struct page *page; + int count = 0; unsigned int tagged = 0;
lru_add_drain(); @@ -39,8 +40,12 @@ static void memfd_tag_pins(struct xa_sta xas_for_each(xas, page, ULONG_MAX) { if (xa_is_value(page)) continue; + page = find_subpage(page, xas->xa_index); - if (page_count(page) - page_mapcount(page) > 1) + count = page_count(page); + if (PageTransCompound(page)) + count -= (1 << compound_order(compound_head(page))) - 1; + if (count - page_mapcount(page) > 1) xas_set_mark(xas, MEMFD_TAG_PINNED);
if (++tagged % XA_CHECK_SCHED) @@ -67,11 +72,12 @@ static int memfd_wait_for_pins(struct ad { XA_STATE(xas, &mapping->i_pages, 0); struct page *page; - int error, scan; + int error, scan, count;
memfd_tag_pins(&xas);
error = 0; + count = 0; for (scan = 0; scan <= LAST_SCAN; scan++) { unsigned int tagged = 0;
@@ -89,8 +95,12 @@ static int memfd_wait_for_pins(struct ad bool clear = true; if (xa_is_value(page)) continue; + page = find_subpage(page, xas.xa_index); - if (page_count(page) - page_mapcount(page) != 1) { + count = page_count(page); + if (PageTransCompound(page)) + count -= (1 << compound_order(compound_head(page))) - 1; + if (count - page_mapcount(page) != 1) { /* * On the last scan, we clean up all those tags * we inserted; but make a note that we still _
Patches currently in -mm which might be from wang.yong12@zte.com.cn are
fix-shmem-huge-page-failed-to-set-f_seal_write-attribute-problem.patch