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([78.43.20.153]) by mrelayeu.kundenserver.de (mreue005) with ESMTPA (Nemesis) id 0LiZ4a-1cUjZy2GYW-00ciAQ; Mon, 24 Oct 2016 17:22:30 +0200 From: Arnd Bergmann To: Greg Kroah-Hartman Cc: Arnd Bergmann , Lars-Peter Clausen , Michael Hennerich , Jonathan Cameron , Hartmut Knaack , Peter Meerwald-Stadler , Alison Schofield , linux-iio@vger.kernel.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org Subject: [PATCH] [v2] staging: iio: ad5933: avoid uninitialized variable in error case Date: Mon, 24 Oct 2016 17:22:01 +0200 Message-Id: <20161024152226.2536749-1-arnd@arndb.de> X-Mailer: git-send-email 2.9.0 X-Provags-ID: V03:K0:Hf5lEL1p0qEw9VIz5OTZOuH4VaEMChmcCY19whvxZDCSbNCnsCL r9O62UcyzW3rGmkKND9FmVBBk9FuQs4cyostBZ4Z0W1jb7lzG29+/bcN63zxLi31XPZyHPU LtHMX4Vi9AcvMOY0XA3X4ta5hGQh0ur440p2/7kvf9rgTJqMBNqgFWF9MLeN4sS72MLH9On fTsxNwfujEjKikdhMsJUA== X-UI-Out-Filterresults: notjunk:1; V01:K0:mhdMJjeBxk4=:GCIuI1opFK9Cyz9Lpqd3HT gDW5Mi+e1CzVaHK3vwpvVjg39kcdOLL1KSAwcWJIo1MIzmsGn8vE12GTxcD37tMiovHWEyuGE gUvrhERsspAlTrCt9p/uz8QW/D7dfEnmtX+lejhDM4Ng57DeLkHv9idBCgl99AbnlXkASUuTX PxSYlmDiQiedNYU44/FplFqXAGOc5v+y7crYF2ymw+rsYbyU1VRc9MYeZGnWm5Gs5K/g0VeFS 3MpprRrt0G+ggTXfwcjtJBVeIgYtGM8ViWATPLcSfEC2lJ6Cp1zChe/VPKZGAXqIR8vaIEJj7 OyYWw2nLKUjQQzT4/F0uTL4iNBVjRtw4W729+sr0qOiXsK3Q6Z5HlbJfI/9Y2H3KeqNU+Wup0 udDTsHNaNo4eG5HsTps6Yu+XUwMrZLqQGyVyNvdcrNUZCQwkNTodEnYHOboPPsBq5vLfb6/ef ccHB7cdFFc2Z8A/ZA1uD4EU57eJ1Tvwfu996U8smze//2lMMBOFZTTofUT1XilvHI0Lnruhs8 8e6x2J4PONVz8XPHxk2H2cvUXWOzWLPdaAo8I814miI9dTLttb8lvZn7820kmbGLEi1Fw1n9L YYCWgZj5I+fqgcR9bg/an8rOsGh8bVWk/2/V5OjRI1KeAzYX7Syp1die47xLWY5Oe7gIUrs+C YUTQ6oTCKwP3K3RpTONm7seUbSRK0q1UABqm5jEyq5kk565s7v+KFiBaS3mp0EvAR3/s= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- v2: handle failure for both affected reads instead of just the one we get a warning for v2: do not retry on failure to avoid looping in case of permanent errors --- drivers/staging/iio/impedance-analyzer/ad5933.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) -- 2.9.0 diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c index 5eecf1cb1028..3892a7470410 100644 --- a/drivers/staging/iio/impedance-analyzer/ad5933.c +++ b/drivers/staging/iio/impedance-analyzer/ad5933.c @@ -655,6 +655,7 @@ static void ad5933_work(struct work_struct *work) __be16 buf[2]; int val[2]; unsigned char status; + int ret; mutex_lock(&indio_dev->mlock); if (st->state == AD5933_CTRL_INIT_START_FREQ) { @@ -662,19 +663,22 @@ 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) { val[0] = be16_to_cpu(buf[0]); @@ -686,8 +690,7 @@ 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) { @@ -700,7 +703,7 @@ 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); }