diff options
author | Peter Feiner <pfeiner@google.com> | 2014-09-26 03:05:18 +0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-09-26 19:10:35 +0400 |
commit | 87e6d49a000fa6148bd539f632706b02c3485c5d (patch) | |
tree | 9d848bb2f91295314dfb423485879cbffb4ad101 | |
parent | 5760a97c7143c208fa3a8f8cad0ed7dd672ebd28 (diff) | |
download | linux-87e6d49a000fa6148bd539f632706b02c3485c5d.tar.xz |
mm: softdirty: addresses before VMAs in PTE holes aren't softdirty
In PTE holes that contain VM_SOFTDIRTY VMAs, unmapped addresses before
VM_SOFTDIRTY VMAs are reported as softdirty by /proc/pid/pagemap. This
bug was introduced in commit 68b5a6524856 ("mm: softdirty: respect
VM_SOFTDIRTY in PTE holes"). That commit made /proc/pid/pagemap look at
VM_SOFTDIRTY in PTE holes but neglected to observe the start of VMAs
returned by find_vma.
Tested:
Wrote a selftest that creates a PMD-sized VMA then unmaps the first
page and asserts that the page is not softdirty. I'm going to send the
pagemap selftest in a later commit.
Signed-off-by: Peter Feiner <pfeiner@google.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Jamie Liu <jamieliu@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | fs/proc/task_mmu.c | 27 |
1 files changed, 18 insertions, 9 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index dfc791c42d64..c34156888d70 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -931,23 +931,32 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end, while (addr < end) { struct vm_area_struct *vma = find_vma(walk->mm, addr); pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2)); - unsigned long vm_end; + /* End of address space hole, which we mark as non-present. */ + unsigned long hole_end; - if (!vma) { - vm_end = end; - } else { - vm_end = min(end, vma->vm_end); - if (vma->vm_flags & VM_SOFTDIRTY) - pme.pme |= PM_STATUS2(pm->v2, __PM_SOFT_DIRTY); + if (vma) + hole_end = min(end, vma->vm_start); + else + hole_end = end; + + for (; addr < hole_end; addr += PAGE_SIZE) { + err = add_to_pagemap(addr, &pme, pm); + if (err) + goto out; } - for (; addr < vm_end; addr += PAGE_SIZE) { + if (!vma) + break; + + /* Addresses in the VMA. */ + if (vma->vm_flags & VM_SOFTDIRTY) + pme.pme |= PM_STATUS2(pm->v2, __PM_SOFT_DIRTY); + for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) { err = add_to_pagemap(addr, &pme, pm); if (err) goto out; } } - out: return err; } |