On Fri, May 10, 2019 at 07:53:24PM +0000, Kuehling, Felix wrote:
> Don't set this flag by default in hmm_vma_do_fault. It is set
> conditionally just a few lines below. Setting it unconditionally
> can lead to handle_mm_fault doing a non-blocking fault, returning
> -EBUSY and unlocking mmap_sem unexpectedly.
>
> Signed-off-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
Reviewed-by: Jérôme Glisse <jglisse@xxxxxxxxxx>
> ---
> mm/hmm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/hmm.c b/mm/hmm.c
> index b65c27d5c119..3c4f1d62202f 100644
> --- a/mm/hmm.c
> +++ b/mm/hmm.c
> @@ -339,7 +339,7 @@ struct hmm_vma_walk {
> static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr,
> bool write_fault, uint64_t *pfn)
> {
> - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_REMOTE;
> + unsigned int flags = FAULT_FLAG_REMOTE;
> struct hmm_vma_walk *hmm_vma_walk = walk->private;
> struct hmm_range *range = hmm_vma_walk->range;
> struct vm_area_struct *vma = walk->vma;
> --
> 2.17.1
>
