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Mon, 27 Apr 2026 13:12:58 -0700 (PDT) Received: from localhost.localdomain ([196.235.239.18]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4463d02f270sm726826f8f.9.2026.04.27.13.12.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Apr 2026 13:12:57 -0700 (PDT) From: Salah Triki To: Jonathan Cameron , David Lechner , =?UTF-8?q?Nuno=20S=C3=A1?= , Andy Shevchenko , Matthias Brugger , AngeloGioacchino Del Regno Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Salah Triki Subject: [PATCH v4] iio: adc: mt6359: fix unchecked return value in mt6358_read_imp Date: Mon, 27 Apr 2026 21:12:38 +0100 Message-ID: <20260427201238.20823-1-salah.triki@gmail.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260427_131300_389375_9EDF1481 X-CRM114-Status: GOOD ( 15.25 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In mt6358_read_imp(), the variable val_v is passed to regmap_read() but the return value is not checked. If the read fails, val_v remains uninitialized and its random stack content is subsequently reported as a measurement result. Initialize val_v to zero to ensure a predictable value is reported in case of bus failure and to prevent potential stack data leakage. This also satisfies static analyzers that might otherwise flag the variable as used uninitialized. Fixes: 3587914bf61 ("iio: adc: Add support for MediaTek MT6357/8/9 Auxiliary ADC") Signed-off-by: Salah Triki --- Changes in v4: - Move val_v initialization just before regmap_read() call as suggested by Andy Shevchenko to improve maintainability. Changes in v3: - Initialize val_v to zero at declaration instead of checking regmap_read() return value, as suggested by Jonathan Cameron and Andy Shevchenko. - Update commit message to reflect this new approach Changes in v2: - Added Fixes tag. - Re-examined the entire driver for unchecked regmap operations. While several regmap_write() and regmap_set_bits() calls also ignore return values, I focused on this specific regmap_read() in mt6358_read_imp() because it leads to an uninitialized variable usage (val_v). This makes this fix critical for reporting correct data to userspace drivers/iio/adc/mt6359-auxadc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/iio/adc/mt6359-auxadc.c b/drivers/iio/adc/mt6359-auxadc.c index 6b9ed9b1fde2..1d9724ef0983 100644 --- a/drivers/iio/adc/mt6359-auxadc.c +++ b/drivers/iio/adc/mt6359-auxadc.c @@ -497,6 +497,7 @@ static int mt6358_read_imp(struct mt6359_auxadc *adc_dev, return ret; /* Read the params before stopping */ + val_v = 0; regmap_read(regmap, reg_adc0 + (cinfo->imp_adc_num << 1), &val_v); mt6358_stop_imp_conv(adc_dev); -- 2.43.0