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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2013-11-22 02:32:09 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-22 04:42:28 +0400
commitc283610e44ec4ccc412dde8b71cf297ed9515f2f (patch)
treedd3c83db8dabefbeb3733cd428cced7c62602beb /Documentation/vm
parent3a72660b07d86d60457ca32080b1ce8c2b628ee2 (diff)
downloadlinux-c283610e44ec4ccc412dde8b71cf297ed9515f2f.tar.xz
x86, mm: do not leak page->ptl for pmd page tables
There are two code paths how page with pmd page table can be freed: pmd_free() and pmd_free_tlb(). I've missed the second one and didn't add page table destructor call there. It leads to leak of page->ptl for pmd page tables, if dynamically allocated page->ptl is in use. The patch adds the missed destructor and modifies documentation accordingly. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Andrey Vagin <avagin@openvz.org> Tested-by: Andrey Vagin <avagin@openvz.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/vm')
-rw-r--r--Documentation/vm/split_page_table_lock6
1 files changed, 3 insertions, 3 deletions
diff --git a/Documentation/vm/split_page_table_lock b/Documentation/vm/split_page_table_lock
index 7521d367f21d..6dea4fd5c961 100644
--- a/Documentation/vm/split_page_table_lock
+++ b/Documentation/vm/split_page_table_lock
@@ -63,9 +63,9 @@ levels.
PMD split lock enabling requires pgtable_pmd_page_ctor() call on PMD table
allocation and pgtable_pmd_page_dtor() on freeing.
-Allocation usually happens in pmd_alloc_one(), freeing in pmd_free(), but
-make sure you cover all PMD table allocation / freeing paths: i.e X86_PAE
-preallocate few PMDs on pgd_alloc().
+Allocation usually happens in pmd_alloc_one(), freeing in pmd_free() and
+pmd_free_tlb(), but make sure you cover all PMD table allocation / freeing
+paths: i.e X86_PAE preallocate few PMDs on pgd_alloc().
With everything in place you can set CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK.