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Message-ID: <494e0309-314b-4982-9575-61f8e690c237@quicinc.com>
Date:   Tue, 29 Aug 2023 06:41:57 -0700
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Subject: Re: [PATCH] wifi: ath10k: fix clang-specific fortify warning
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To:     Dmitry Antipov <dmantipov@yandex.ru>
CC:     Kalle Valo <kvalo@kernel.org>, <ath10k@lists.infradead.org>,
        <linux-wireless@vger.kernel.org>
References: <20230829093652.234537-1-dmantipov@yandex.ru>
From:   Jeff Johnson <quic_jjohnson@quicinc.com>
In-Reply-To: <20230829093652.234537-1-dmantipov@yandex.ru>
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On 8/29/2023 2:36 AM, Dmitry Antipov wrote:
> When compiling with clang 16.0.6 and CONFIG_FORTIFY_SOURCE=y, I've
> noticed the following (somewhat confusing due to absence of an actual
> source code location):
> 
> In file included from drivers/net/wireless/ath/ath10k/debug.c:8:
> In file included from ./include/linux/module.h:13:
> In file included from ./include/linux/stat.h:19:
> In file included from ./include/linux/time.h:60:
> In file included from ./include/linux/time32.h:13:
> In file included from ./include/linux/timex.h:67:
> In file included from ./arch/x86/include/asm/timex.h:5:
> In file included from ./arch/x86/include/asm/processor.h:23:
> In file included from ./arch/x86/include/asm/msr.h:11:
> In file included from ./arch/x86/include/asm/cpumask.h:5:
> In file included from ./include/linux/cpumask.h:12:
> In file included from ./include/linux/bitmap.h:11:
> In file included from ./include/linux/string.h:254:
> ./include/linux/fortify-string.h:592:4: warning: call to '__read_overflow2_field'
> declared with 'warning' attribute: detected read beyond size of field (2nd
> parameter); maybe use struct_group()? [-Wattribute-warning]
>                          __read_overflow2_field(q_size_field, size);
> 
> The compiler actually complains on 'ath10k_debug_get_et_strings()' where
> fortification logic inteprets call to 'memcpy()' as an attempt to copy
> the whole 'ath10k_gstrings_stats' array from it's first member and so
> issues an overread warning. This warning may be silenced by passing
> an address of the whole array and not the first member to 'memcpy()'.
> 
> Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>

Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>

> ---
>   drivers/net/wireless/ath/ath10k/debug.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/ath/ath10k/debug.c b/drivers/net/wireless/ath/ath10k/debug.c
> index f9518e1c9903..fe89bc61e531 100644
> --- a/drivers/net/wireless/ath/ath10k/debug.c
> +++ b/drivers/net/wireless/ath/ath10k/debug.c
> @@ -1140,7 +1140,7 @@ void ath10k_debug_get_et_strings(struct ieee80211_hw *hw,
>   				 u32 sset, u8 *data)
>   {
>   	if (sset == ETH_SS_STATS)
> -		memcpy(data, *ath10k_gstrings_stats,
> +		memcpy(data, ath10k_gstrings_stats,
>   		       sizeof(ath10k_gstrings_stats));
>   }
>