Re: [PATCH net-next 1/2] ath10k: fix gcc-10 zero-length-bounds warnings

From: Gustavo A. R. Silva
Date: Sat May 09 2020 - 11:44:02 EST


Arnd,

On Sat, May 09, 2020 at 02:06:32PM +0200, Arnd Bergmann wrote:
> gcc-10 started warning about out-of-bounds access for zero-length
> arrays:
>
> In file included from drivers/net/wireless/ath/ath10k/core.h:18,
> from drivers/net/wireless/ath/ath10k/htt_rx.c:8:
> drivers/net/wireless/ath/ath10k/htt_rx.c: In function 'ath10k_htt_rx_tx_fetch_ind':
> drivers/net/wireless/ath/ath10k/htt.h:1683:17: warning: array subscript 65535 is outside the bounds of an interior zero-length array 'struct htt_tx_fetch_record[0]' [-Wzero-length-bounds]
> 1683 | return (void *)&ind->records[le16_to_cpu(ind->num_records)];
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/wireless/ath/ath10k/htt.h:1676:29: note: while referencing 'records'
> 1676 | struct htt_tx_fetch_record records[0];
> | ^~~~~~~
>
> Make records[] a flexible array member to allow this, moving it behind
> the other zero-length member that is not accessed in a way that gcc
> warns about.
>
> Fixes: 3ba225b506a2 ("treewide: Replace zero-length array with flexible-array member")

This treewide patch no longer contains changes for ath10k. I removed them
since Monday (05/04/2020). So, this "Fixes" tag does not apply.

Thanks
--
Gustavo

> Fixes: 22e6b3bc5d96 ("ath10k: add new htt definitions")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> drivers/net/wireless/ath/ath10k/htt.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/ath/ath10k/htt.h b/drivers/net/wireless/ath/ath10k/htt.h
> index 8f3710cf28f4..aa056a186402 100644
> --- a/drivers/net/wireless/ath/ath10k/htt.h
> +++ b/drivers/net/wireless/ath/ath10k/htt.h
> @@ -1673,8 +1673,8 @@ struct htt_tx_fetch_ind {
> __le32 token;
> __le16 num_resp_ids;
> __le16 num_records;
> - struct htt_tx_fetch_record records[0];
> __le32 resp_ids[0]; /* ath10k_htt_get_tx_fetch_ind_resp_ids() */
> + struct htt_tx_fetch_record records[];
> } __packed;
>
> static inline void *
> --
> 2.26.0
>