Re: [PATCH v2 2/3] mm, swap: distinguish a malformed swap entry from a dying device

[Kairui Song]

On Thu, Aug 13, 2026 at 03:02:21AM +0800, Breno Leitao wrote:
> get_swap_device() returns NULL for two different things: an entry whose
> type names no swap device or whose offset is past the end of one, and a
> device that swapoff is taking away. The first never becomes valid, the
> second does, and callers cannot tell them apart.
> 
> Return ERR_PTR(-EIO) for the two malformed cases and keep NULL for
> swapoff. copy_nonpresent_pte() already reports -EIO for the same
> corruption on the fork path.
> 
> Callers bail out on failure either way, so switch them to
> IS_ERR_OR_NULL() and clear si where the cleanup path would otherwise
> put an ERR_PTR. No functional change.
> 
> Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
> ---
>  mm/memory.c      |  6 ++++--
>  mm/mincore.c     |  2 +-
>  mm/shmem.c       |  2 +-
>  mm/swap_state.c  |  4 ++--
>  mm/swapfile.c    | 14 +++++++++-----
>  mm/userfaultfd.c |  3 ++-
>  mm/zswap.c       |  2 +-
>  7 files changed, 20 insertions(+), 13 deletions(-)
> 

Looks good, thanks!

Acked-by: Kairui Song <kasong@xxxxxxxxxxx>