On Mon, Jul 01, 2024 at 11:31:59AM +0800, Jason Wang wrote:
> remap_pfn_page() should not be called in the fault handler as it may
> change the vma->flags which may trigger lockdep warning since the vma
> write lock is not held. Actually there's no need to modify the
> vma->flags as it has been set in the mmap(). So this patch switches to
> use vmf_insert_pfn() instead.
>
> Reported-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
> Tested-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
> Fixes: ddd89d0a059d ("vhost_vdpa: support doorbell mapping via mmap")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> drivers/vhost/vdpa.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 63a53680a85c..6b9c12acf438 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -1483,13 +1483,7 @@ static vm_fault_t vhost_vdpa_fault(struct vm_fault *vmf)
>
> notify = ops->get_vq_notification(vdpa, index);
>
> - vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
> - if (remap_pfn_range(vma, vmf->address & PAGE_MASK,
> - PFN_DOWN(notify.addr), PAGE_SIZE,
> - vma->vm_page_prot))
> - return VM_FAULT_SIGBUS;
> -
> - return VM_FAULT_NOPAGE;
> + return vmf_insert_pfn(vma, vmf->address & PAGE_MASK, PFN_DOWN(notify.addr));
> }
>
> static const struct vm_operations_struct vhost_vdpa_vm_ops = {
> --
> 2.31.1
>
>
I would only consider pasting an example warning log. (It's my
suggestion only).
Anyway, the patch looks OK to me.
Thanks,
Reviewed-by: Michal Kubiak <michal.kubiak@xxxxxxxxx>
