From: Kalle Valo <kvalo@codeaurora.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
Subject: Re: [PATCH net-next] wlcore: fix overlapping snprintf arguments in debugfs
Date: Sat, 17 Apr 2021 18:02:19 +0000 (UTC) [thread overview]
Message-ID: <20210417180219.6A4D0C43460@smtp.codeaurora.org> (raw)
In-Reply-To: <20210323125723.1961432-1-arnd@kernel.org>
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
prev parent reply other threads:[~2021-04-17 18:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-23 12:57 [PATCH net-next] wlcore: fix overlapping snprintf arguments in debugfs Arnd Bergmann
2021-04-07 11:41 ` Kalle Valo
2021-04-17 18:02 ` Kalle Valo [this message]
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