Re: [PATCH v3 3/3] mm: use vma_start_write_killable() in process_vma_walk_lock()

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Wed, 25 Feb 2026 23:06:09 -0800
Suren Baghdasaryan <surenb@google.com> wrote:

> Replace vma_start_write() with vma_start_write_killable() when
> process_vma_walk_lock() is used with PGWALK_WRLOCK option.
> Adjust its direct and indirect users to check for a possible error
> and handle it. Ensure users handle EINTR correctly and do not ignore
> it.
> 
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> ---
>  arch/s390/kvm/kvm-s390.c |  2 +-
>  fs/proc/task_mmu.c       |  5 ++++-
>  mm/mempolicy.c           | 14 +++++++++++---
>  mm/pagewalk.c            | 20 ++++++++++++++------
>  mm/vma.c                 | 22 ++++++++++++++--------
>  mm/vma.h                 |  6 ++++++
>  6 files changed, 50 insertions(+), 19 deletions(-)
> 
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 7a175d86cef0..337e4f7db63a 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -2948,7 +2948,7 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
>  		}
>  		/* must be called without kvm->lock */
>  		r = kvm_s390_handle_pv(kvm, &args);
> -		if (copy_to_user(argp, &args, sizeof(args))) {
> +		if (r != -EINTR && copy_to_user(argp, &args, sizeof(args))) {
>  			r = -EFAULT;
>  			break;
>  		}

can you very briefly explain how we can end up with -EINTR here?

do I understand correctly that -EINTR is possible here only if the
process is being killed?

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