Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754414AbcKYI5t (ORCPT ); Fri, 25 Nov 2016 03:57:49 -0500 Received: from mx2.suse.de ([195.135.220.15]:45351 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752927AbcKYIbe (ORCPT ); Fri, 25 Nov 2016 03:31:34 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Arnd Bergmann , Jonathan Cameron , Jiri Slaby Subject: [PATCH 3.12 057/127] staging: iio: ad5933: avoid uninitialized variable in error case Date: Fri, 25 Nov 2016 09:29:30 +0100 Message-Id: <8b4458df0fd4de18cb8232380f0897a08bdb95d4.1480062521.git.jslaby@suse.cz> X-Mailer: git-send-email 2.10.2 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3024 Lines: 88 From: Arnd Bergmann 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 34eee70a7b82b09dbda4cb453e0e21d460dae226 upstream. The ad5933_i2c_read function returns an error code to indicate whether it could read data or not. However ad5933_work() ignores this return code and just accesses the data unconditionally, which gets detected by gcc as a possible bug: drivers/staging/iio/impedance-analyzer/ad5933.c: In function 'ad5933_work': drivers/staging/iio/impedance-analyzer/ad5933.c:649:16: warning: 'status' may be used uninitialized in this function [-Wmaybe-uninitialized] This adds minimal error handling so we only evaluate the data if it was correctly read. Link: https://patchwork.kernel.org/patch/8110281/ Signed-off-by: Arnd Bergmann Acked-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Signed-off-by: Jiri Slaby --- drivers/staging/iio/impedance-analyzer/ad5933.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c index bc23d66a7a1e..1ff17352abde 100644 --- a/drivers/staging/iio/impedance-analyzer/ad5933.c +++ b/drivers/staging/iio/impedance-analyzer/ad5933.c @@ -646,6 +646,7 @@ static void ad5933_work(struct work_struct *work) struct iio_dev *indio_dev = i2c_get_clientdata(st->client); signed short buf[2]; unsigned char status; + int ret; mutex_lock(&indio_dev->mlock); if (st->state == AD5933_CTRL_INIT_START_FREQ) { @@ -653,19 +654,22 @@ static void ad5933_work(struct work_struct *work) ad5933_cmd(st, AD5933_CTRL_START_SWEEP); st->state = AD5933_CTRL_START_SWEEP; schedule_delayed_work(&st->work, st->poll_time_jiffies); - mutex_unlock(&indio_dev->mlock); - return; + goto out; } - ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status); + ret = ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status); + if (ret) + goto out; if (status & AD5933_STAT_DATA_VALID) { int scan_count = bitmap_weight(indio_dev->active_scan_mask, indio_dev->masklength); - ad5933_i2c_read(st->client, + ret = ad5933_i2c_read(st->client, test_bit(1, indio_dev->active_scan_mask) ? AD5933_REG_REAL_DATA : AD5933_REG_IMAG_DATA, scan_count * 2, (u8 *)buf); + if (ret) + goto out; if (scan_count == 2) { buf[0] = be16_to_cpu(buf[0]); @@ -677,8 +681,7 @@ static void ad5933_work(struct work_struct *work) } else { /* no data available - try again later */ schedule_delayed_work(&st->work, st->poll_time_jiffies); - mutex_unlock(&indio_dev->mlock); - return; + goto out; } if (status & AD5933_STAT_SWEEP_DONE) { @@ -690,7 +693,7 @@ static void ad5933_work(struct work_struct *work) ad5933_cmd(st, AD5933_CTRL_INC_FREQ); schedule_delayed_work(&st->work, st->poll_time_jiffies); } - +out: mutex_unlock(&indio_dev->mlock); } -- 2.10.2