Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Sender: kvalo=codeaurora.org@mg.codeaurora.org
DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 786E1C433F1
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Subject: Re: [PATCH net-next] wlcore: fix overlapping snprintf arguments in
 debugfs
From:   Kalle Valo <kvalo@codeaurora.org>
In-Reply-To: <20210323125723.1961432-1-arnd@kernel.org>
References: <20210323125723.1961432-1-arnd@kernel.org>
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Luciano Coelho <coelho@ti.com>, Arik Nemtsov <arik@wizery.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Lee Jones <lee.jones@linaro.org>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
User-Agent: pwcli/0.1.0-git (https://github.com/kvalo/pwcli/) Python/3.5.2
Message-Id: <20210417180219.6A4D0C43460@smtp.codeaurora.org>
Date:   Sat, 17 Apr 2021 18:02:19 +0000 (UTC)
Precedence: bulk

Arnd Bergmann <arnd@kernel.org> wrote:

> From: Arnd Bergmann <arnd@arndb.de>
> 
> gcc complains about undefined behavior in calling snprintf()
> with the same buffer as input and output:
> 
> drivers/net/wireless/ti/wl18xx/debugfs.c: In function 'diversity_num_of_packets_per_ant_read':
> drivers/net/wireless/ti/wl18xx/../wlcore/debugfs.h:86:3: error: 'snprintf' argument 4 overlaps destination object 'buf' [-Werror=restrict]
>    86 |   snprintf(buf, sizeof(buf), "%s[%d] = %d\n",  \
>       |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    87 |     buf, i, stats->sub.name[i]);   \
>       |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/wireless/ti/wl18xx/debugfs.c:24:2: note: in expansion of macro 'DEBUGFS_FWSTATS_FILE_ARRAY'
>    24 |  DEBUGFS_FWSTATS_FILE_ARRAY(a, b, c, wl18xx_acx_statistics)
>       |  ^~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/net/wireless/ti/wl18xx/debugfs.c:159:1: note: in expansion of macro 'WL18XX_DEBUGFS_FWSTATS_FILE_ARRAY'
>   159 | WL18XX_DEBUGFS_FWSTATS_FILE_ARRAY(diversity, num_of_packets_per_ant,
> 
> There are probably other ways of handling the debugfs file, without
> using on-stack buffers, but a simple workaround here is to remember the
> current position in the buffer and just keep printing in there.
> 
> Fixes: bcca1bbdd412 ("wlcore: add debugfs macro to help print fw statistics arrays")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Patch applied to wireless-drivers-next.git, thanks.

7b0e2c4f6be3 wlcore: fix overlapping snprintf arguments in debugfs

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20210323125723.1961432-1-arnd@kernel.org/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches