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| author | Zi Yan <zi.yan@cs.rutgers.edu> | 2017-11-02 15:59:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-03 07:39:19 -0700 |
| commit | dd8a67f9a37c74b61e5e050924ceec9ffb4f8c3c (patch) | |
| tree | 047993d332418b884aa60f0acf08932842d47701 /mm/huge_memory.c | |
| parent | e08b1877452a0055c65f6394163ce5a0fbd720a3 (diff) | |
| download | lwn-dd8a67f9a37c74b61e5e050924ceec9ffb4f8c3c.tar.gz lwn-dd8a67f9a37c74b61e5e050924ceec9ffb4f8c3c.zip | |
mm/huge_memory.c: deposit page table when copying a PMD migration entry
We need to deposit pre-allocated PTE page table when a PMD migration
entry is copied in copy_huge_pmd(). Otherwise, we will leak the
pre-allocated page and cause a NULL pointer dereference later in
zap_huge_pmd().
The missing counters during PMD migration entry copy process are added
as well.
The bug report is here: https://lkml.org/lkml/2017/10/29/214
Link: http://lkml.kernel.org/r/20171030144636.4836-1-zi.yan@sent.com
Fixes: 84c3fc4e9c563 ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 269b5df58543..1981ed697dab 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -941,6 +941,9 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, pmd = pmd_swp_mksoft_dirty(pmd); set_pmd_at(src_mm, addr, src_pmd, pmd); } + add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); + atomic_long_inc(&dst_mm->nr_ptes); + pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); set_pmd_at(dst_mm, addr, dst_pmd, pmd); ret = 0; goto out_unlock; |