This patch resets current pagemap-entry if current pte isn't present,
or if current vma is over. Otherwise pagemap reports last entry again and again.
non-present pte reporting was broken in commit v3.3-3738-g092b50b
("pagemap: introduce data structure for pagemap entry")
reporting for holes was broken in commit v3.3-3734-g5aaabe8
("pagemap: avoid splitting thp when reading /proc/pid/pagemap")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
Reported-by: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index a580c69..9f9c033 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -747,6 +747,8 @@ static void pte_to_pagemap_entry(pagemap_entry_t *pme, pte_t pte)
else if (pte_present(pte))
*pme = make_pme(PM_PFRAME(pte_pfn(pte))
| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);
+ else
+ *pme = make_pme(PM_NOT_PRESENT);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -761,6 +763,8 @@ static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme,
if (pmd_present(pmd))
*pme = make_pme(PM_PFRAME(pmd_pfn(pmd) + offset)
| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);
+ else
+ *pme = make_pme(PM_NOT_PRESENT);
}
#else
static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme,
@@ -801,8 +805,10 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
/* check to see if we've left 'vma' behind
* and need a new, higher one */
- if (vma && (addr >= vma->vm_end))
+ if (vma && (addr >= vma->vm_end)) {
vma = find_vma(walk->mm, addr);
+ pme = make_pme(PM_NOT_PRESENT);
+ }
/* check that 'vma' actually covers this address,
* and that it isn't a huge page vma */
@@ -830,6 +836,8 @@ static void huge_pte_to_pagemap_entry(pagemap_entry_t *pme,
if (pte_present(pte))
*pme = make_pme(PM_PFRAME(pte_pfn(pte) + offset)
| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);
+ else
+ *pme = make_pme(PM_NOT_PRESENT);
}
/* This function walks within one hugetlb entry in the single call */
@@ -839,7 +847,7 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
{
struct pagemapread *pm = walk->private;
int err = 0;
- pagemap_entry_t pme = make_pme(PM_NOT_PRESENT);
+ pagemap_entry_t pme;
for (; addr != end; addr += PAGE_SIZE) {
int offset = (addr & ~hmask) >> PAGE_SHIFT;
--
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