On Wed, Jun 09, 2021 at 05:07:29PM -0400, schumaker.anna@xxxxxxxxx wrote:
> From: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
>
> This seems to happen fairly easily during READ_PLUS testing on NFS v4.2.
Yep, I hit a KASAN warning here every time, and this fixes it,
thanks.--b.
> I found that we could end up accessing xdr->buf->pages[pgnr] with a pgnr
> greater than the number of pages in the array. So let's just return
> early if we're setting base to a point at the end of the page data and
> let xdr_set_tail_base() handle setting up the buffer pointers instead.
>
> Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
> ---
> net/sunrpc/xdr.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
> index 3964ff74ee51..ca10ba2626f2 100644
> --- a/net/sunrpc/xdr.c
> +++ b/net/sunrpc/xdr.c
> @@ -1230,10 +1230,9 @@ static unsigned int xdr_set_page_base(struct xdr_stream *xdr,
> void *kaddr;
>
> maxlen = xdr->buf->page_len;
> - if (base >= maxlen) {
> - base = maxlen;
> - maxlen = 0;
> - } else
> + if (base >= maxlen)
> + return 0;
> + else
> maxlen -= base;
> if (len > maxlen)
> len = maxlen;
> --
> 2.32.0
