| Message ID | 1573218104-11021-2-git-send-email-lixinhai.lxh@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: Fix checking unmapped holes for mbind | expand |
On Fri, Nov 08, 2019 at 09:01:43PM +0800, Li Xinhai wrote: > Checking unmapped hole and updating the previous vma must be handled first, > otherwise the unmapped hole could be calculated from a wrong previous vma. > > Several commits were relevant to this error: > commit 6f4576e3687b > ("mempolicy: apply page table walker on queue_pages_range()"), > This commit was correct, the VM_PFNMAP check was after updateing previous > vma > > commit 48684a65b4e3 > (mm: pagewalk: fix misbehavior of walk_page_range for vma(VM_PFNMAP)), > This commit added VM_PFNMAP check before updateing previous vma. Then, > there were two VM_PFNMAP check did same thing twice. > > commit acda0c334028 > (mm/mempolicy.c: get rid of duplicated check for vma(VM_PFNMAP) in queue_page > s_range()), > This commit tried to fix the duplicated VM_PFNMAP check, but it wrongly > removed the one which was after updateing vma. > > Fixes: acda0c334028 (mm/mempolicy.c: get rid of duplicated check for vma(VM_PFNMAP) in queue_page > s_range()) > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> > Cc: Michal Hocko <mhocko@suse.com> > Cc: Vlastimil Babka <vbabka@suse.cz> > Cc: Hugh Dickins <hughd@google.com> > Cc: linux-man <linux-man@vger.kernel.org> > Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 4ae967b..807f06f 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -618,6 +618,16 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end, unsigned long endvma = vma->vm_end; unsigned long flags = qp->flags; + /* range check first */ + if (!(flags & MPOL_MF_DISCONTIG_OK)) { + if (!vma->vm_next && vma->vm_end < end) + return -EFAULT; + if (qp->prev && qp->prev->vm_end < vma->vm_start) + return -EFAULT; + } + + qp->prev = vma; + /* * Need check MPOL_MF_STRICT to return -EIO if possible * regardless of vma_migratable @@ -631,15 +641,6 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end, if (vma->vm_start > start) start = vma->vm_start; - if (!(flags & MPOL_MF_DISCONTIG_OK)) { - if (!vma->vm_next && vma->vm_end < end) - return -EFAULT; - if (qp->prev && qp->prev->vm_end < vma->vm_start) - return -EFAULT; - } - - qp->prev = vma; - if (flags & MPOL_MF_LAZY) { /* Similar to task_numa_work, skip inaccessible VMAs */ if (!is_vm_hugetlb_page(vma) &&
Checking unmapped hole and updating the previous vma must be handled first, otherwise the unmapped hole could be calculated from a wrong previous vma. Several commits were relevant to this error: commit 6f4576e3687b ("mempolicy: apply page table walker on queue_pages_range()"), This commit was correct, the VM_PFNMAP check was after updateing previous vma commit 48684a65b4e3 (mm: pagewalk: fix misbehavior of walk_page_range for vma(VM_PFNMAP)), This commit added VM_PFNMAP check before updateing previous vma. Then, there were two VM_PFNMAP check did same thing twice. commit acda0c334028 (mm/mempolicy.c: get rid of duplicated check for vma(VM_PFNMAP) in queue_page s_range()), This commit tried to fix the duplicated VM_PFNMAP check, but it wrongly removed the one which was after updateing vma. Fixes: acda0c334028 (mm/mempolicy.c: get rid of duplicated check for vma(VM_PFNMAP) in queue_page s_range()) Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: linux-man <linux-man@vger.kernel.org> Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com> --- mm/mempolicy.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-)