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Subject[PATCH] mm/smaps: Don't access young/dirty bit if pte unpresent
Date
These bits should only be valid when the ptes are present.  Introducing two
booleans for it and set it to false when !pte_present().

Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Fixes: b1d4d9e0cbd0 ("proc/smaps: carefully handle migration entries", 2012-05-31)
Signed-off-by: Peter Xu <peterx@redhat.com>
---
fs/proc/task_mmu.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 9913f3be9fd2..482f91577f8c 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -527,10 +527,12 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
struct vm_area_struct *vma = walk->vma;
bool locked = !!(vma->vm_flags & VM_LOCKED);
struct page *page = NULL;
- bool migration = false;
+ bool migration = false, young = false, dirty = false;

if (pte_present(*pte)) {
page = vm_normal_page(vma, addr, *pte);
+ young = pte_young(*pte);
+ dirty = pte_dirty(*pte);
} else if (is_swap_pte(*pte)) {
swp_entry_t swpent = pte_to_swp_entry(*pte);

@@ -560,8 +562,7 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
if (!page)
return;

- smaps_account(mss, page, false, pte_young(*pte), pte_dirty(*pte),
- locked, migration);
+ smaps_account(mss, page, false, young, dirty, locked, migration);
}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
--
2.32.0
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