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Date:   Tue, 5 Dec 2023 14:37:38 -0800 (PST)
From:   Stefano Stabellini <sstabellini@kernel.org>
To:     Juergen Gross <jgross@suse.com>
cc:     linux-kernel@vger.kernel.org,
        Stefano Stabellini <sstabellini@kernel.org>,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>,
        xen-devel@lists.xenproject.org, Pry Mar <pryorm09@gmail.com>
Subject: Re: [PATCH] xen: update PV-device interface headers
In-Reply-To: <20231205115121.11627-1-jgross@suse.com>
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References: <20231205115121.11627-1-jgross@suse.com>
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On Tue, 4 Dec 2023, Juergen Gross wrote:
> Update the Xen PV-device interface headers in order to avoid undefined
> behavior with flexible arrays being defined with one array element.
> 
> Reported-by: Pry Mar <pryorm09@gmail.com>
> Signed-off-by: Juergen Gross <jgross@suse.com>

Acked-by: Stefano Stabellini <sstabellini@kernel.org>

> ---
>  include/xen/interface/io/displif.h | 2 +-
>  include/xen/interface/io/ring.h    | 2 +-
>  include/xen/interface/io/sndif.h   | 2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/include/xen/interface/io/displif.h b/include/xen/interface/io/displif.h
> index 18417b017869..60e42d3b760e 100644
> --- a/include/xen/interface/io/displif.h
> +++ b/include/xen/interface/io/displif.h
> @@ -537,7 +537,7 @@ struct xendispl_dbuf_create_req {
>  
>  struct xendispl_page_directory {
>  	grant_ref_t gref_dir_next_page;
> -	grant_ref_t gref[1]; /* Variable length */
> +	grant_ref_t gref[];
>  };
>  
>  /*
> diff --git a/include/xen/interface/io/ring.h b/include/xen/interface/io/ring.h
> index ba4c4274b714..4fef1efcdcab 100644
> --- a/include/xen/interface/io/ring.h
> +++ b/include/xen/interface/io/ring.h
> @@ -95,7 +95,7 @@ struct __name##_sring {                                                 \
>      RING_IDX req_prod, req_event;                                       \
>      RING_IDX rsp_prod, rsp_event;                                       \
>      uint8_t __pad[48];                                                  \
> -    union __name##_sring_entry ring[1]; /* variable-length */           \
> +    union __name##_sring_entry ring[];                                  \
>  };                                                                      \
>                                                                          \
>  /* "Front" end's private variables */                                   \
> diff --git a/include/xen/interface/io/sndif.h b/include/xen/interface/io/sndif.h
> index 445657cdb1de..b818517588b5 100644
> --- a/include/xen/interface/io/sndif.h
> +++ b/include/xen/interface/io/sndif.h
> @@ -659,7 +659,7 @@ struct xensnd_open_req {
>  
>  struct xensnd_page_directory {
>  	grant_ref_t gref_dir_next_page;
> -	grant_ref_t gref[1]; /* Variable length */
> +	grant_ref_t gref[];
>  };
>  
>  /*
> -- 
> 2.35.3
>