@@ -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
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-f_seal_write-attribute-problem.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/fix-shmem-huge-page-failed-to-set-f_seal_write-attribute-problem.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ 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(-)