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Miller" , Jakub Kicinski , Luciano Coelho , Arik Nemtsov , Arnd Bergmann , Lee Jones , 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 References: <20210323125723.1961432-1-arnd@kernel.org> Date: Wed, 07 Apr 2021 14:41:57 +0300 In-Reply-To: <20210323125723.1961432-1-arnd@kernel.org> (Arnd Bergmann's message of "Tue, 23 Mar 2021 13:57:14 +0100") Message-ID: <8735w2nwxm.fsf@codeaurora.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Arnd Bergmann writes: > From: Arnd Bergmann > > 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 > --- > drivers/net/wireless/ti/wlcore/boot.c | 13 ++++++++----- > drivers/net/wireless/ti/wlcore/debugfs.h | 7 ++++--- This should go to wireless-drivers-next, not net-next. -- https://patchwork.kernel.org/project/linux-wireless/list/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches