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Commit b83d7e43 authored by Huang Ying's avatar Huang Ying Committed by Linus Torvalds
Browse files

mm, /proc/pid/pagemap: fix soft dirty marking for PMD migration entry 

When the pagetable is walked in the implementation of /proc/<pid>/pagemap,
pmd_soft_dirty() is used for both the PMD huge page map and the PMD
migration entries.  That is wrong, pmd_swp_soft_dirty() should be used
for the PMD migration entries instead because the different page table
entry flag is used.

As a result, /proc/pid/pagemap may report incorrect soft dirty information
for PMD migration entries.

Link: http://lkml.kernel.org/r/20171017081818.31795-1-ying.huang@intel.com


Fixes: 84c3fc4e ("mm: thp: check pmd migration entry in common path")
Signed-off-by: default avatar"Huang, Ying" <ying.huang@intel.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Daniel Colascione <dancol@google.com>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1e392147

fs/proc/task_mmu.c

+5 −1
Original line number Diff line number Diff line
@@ -1311,13 +1311,15 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end, 
		pmd_t pmd = *pmdp;

		struct page *page = NULL;



		if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(pmd))

		if (vma->vm_flags & VM_SOFTDIRTY)

			flags |= PM_SOFT_DIRTY;



		if (pmd_present(pmd)) {

			page = pmd_page(pmd);



			flags |= PM_PRESENT;

			if (pmd_soft_dirty(pmd))

				flags |= PM_SOFT_DIRTY;

			if (pm->show_pfn)

				frame = pmd_pfn(pmd) +

					((addr & ~PMD_MASK) >> PAGE_SHIFT);
@@ -1329,6 +1331,8 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end, 
			frame = swp_type(entry) |

				(swp_offset(entry) << MAX_SWAPFILES_SHIFT);

			flags |= PM_SWAP;

			if (pmd_swp_soft_dirty(pmd))

				flags |= PM_SOFT_DIRTY;

			VM_BUG_ON(!is_pmd_migration_entry(pmd));

			page = migration_entry_to_page(entry);

		}