On Mon, Jun 10, 2019 at 03:58:23PM +0200, Michal Hocko wrote: > Just a heads up. Ajay Kaher has noticed that mlx4 driver is missing the > check in 4.14 [1] and 4.4 seems to have the same problem. I will wait > for more review before reposting v3. The incremental diff is: > > diff --git a/drivers/infiniband/hw/mlx4/main.c b/drivers/infiniband/hw/mlx4/main.c > index 67c4c73343d4..6968154a073e 100644 > +++ b/drivers/infiniband/hw/mlx4/main.c > @@ -1042,6 +1042,8 @@ static void mlx4_ib_disassociate_ucontext(struct ib_ucontext *ibcontext) > * mlx4_ib_vma_close(). > */ > down_write(&owning_mm->mmap_sem); > + if (!mmget_still_valid(owning_mm)) > + goto skip_mm; > for (i = 0; i < HW_BAR_COUNT; i++) { > vma = context->hw_bar_info[i].vma; > if (!vma) > @@ -1061,6 +1063,7 @@ static void mlx4_ib_disassociate_ucontext(struct ib_ucontext *ibcontext) > context->hw_bar_info[i].vma->vm_ops = NULL; > } > > +skip_mm: > up_write(&owning_mm->mmap_sem); > mmput(owning_mm); > put_task_struct(owning_process); Looks OK to me Jason