The patch titled
Subject: mm: fix memory leak in copy_huge_pmd()
has been added to the -mm tree. Its filename is
mm-fix-memory-leak-in-copy_huge_pmd.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-fix-memory-leak-in-copy_huge_pmd.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-memory-leak-in-copy_huge_pmd.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/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
Subject: mm: fix memory leak in copy_huge_pmd()
We allocate a pgtable but do not attach it to anything if the PMD is in a
DAX VMA, causing it to leak.
We certainly try to not free pgtables associated with the huge zero page
if the zero page is in a DAX VMA, so I think this is the right solution.
This needs to be properly audited.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: "Kirill A . Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff -puN mm/huge_memory.c~mm-fix-memory-leak-in-copy_huge_pmd mm/huge_memory.c
--- a/mm/huge_memory.c~mm-fix-memory-leak-in-copy_huge_pmd
+++ a/mm/huge_memory.c
@@ -858,7 +858,8 @@ static bool set_huge_zero_page(pgtable_t
return false;
entry = mk_pmd(zero_page, vma->vm_page_prot);
entry = pmd_mkhuge(entry);
- pgtable_trans_huge_deposit(mm, pmd, pgtable);
+ if (pgtable)
+ pgtable_trans_huge_deposit(mm, pmd, pgtable);
set_pmd_at(mm, haddr, pmd, entry);
atomic_long_inc(&mm->nr_ptes);
return true;
@@ -1036,13 +1037,15 @@ int copy_huge_pmd(struct mm_struct *dst_
spinlock_t *dst_ptl, *src_ptl;
struct page *src_page;
pmd_t pmd;
- pgtable_t pgtable;
+ pgtable_t pgtable = NULL;
int ret;
- ret = -ENOMEM;
- pgtable = pte_alloc_one(dst_mm, addr);
- if (unlikely(!pgtable))
- goto out;
+ if (!vma_is_dax(vma)) {
+ ret = -ENOMEM;
+ pgtable = pte_alloc_one(dst_mm, addr);
+ if (unlikely(!pgtable))
+ goto out;
+ }
dst_ptl = pmd_lock(dst_mm, dst_pmd);
src_ptl = pmd_lockptr(src_mm, src_pmd);
@@ -1073,7 +1076,7 @@ int copy_huge_pmd(struct mm_struct *dst_
goto out_unlock;
}
- if (pmd_trans_huge(pmd)) {
+ if (!vma_is_dax(vma)) {
/* thp accounting separate from pmd_devmap accounting */
src_page = pmd_page(pmd);
VM_BUG_ON_PAGE(!PageHead(src_page), src_page);
_
Patches currently in -mm which might be from matthew.r.wilcox@xxxxxxxxx are
mm-fix-memory-leak-in-copy_huge_pmd.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
