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@xxxxxxxxxxxxxxxxxxxx>
> Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> Cc: linux-man <linux-man@xxxxxxxxxxxxxxx>
> Signed-off-by: Li Xinhai <lixinhai.lxh@xxxxxxxxx>
Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
