linux-kernel - [PATCH] iio: chemical: set val parameter only on success

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Message-Id: <20211224150833.3278236-1-trix@redhat.com>
Date:   Fri, 24 Dec 2021 07:08:33 -0800
From:   trix@...hat.com
To:     jacopo@...ndi.org, jic23@...nel.org, lars@...afoo.de,
        nathan@...nel.org, ndesaulniers@...gle.com
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev, Tom Rix <trix@...hat.com>
Subject: [PATCH] iio: chemical: set val parameter only on success

From: Tom Rix <trix@...hat.com>

Clang static analysis reports this representative warning

sunrise_co2.c:410:9: warning: Assigned value is garbage or undefined
  *val = value;
       ^ ~~~~~

The ealier call to sunrise_read_word can fail without setting
value.  So defer setting val until we know the read was successful.

Fixes: c397894e24f1 ("iio: chemical: Add Senseair Sunrise 006-0-007 driver")
Signed-off-by: Tom Rix <trix@...hat.com>
---
 drivers/iio/chemical/sunrise_co2.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/chemical/sunrise_co2.c b/drivers/iio/chemical/sunrise_co2.c
index 233bd0f379c93..8440dc0c77cfe 100644
--- a/drivers/iio/chemical/sunrise_co2.c
+++ b/drivers/iio/chemical/sunrise_co2.c
@@ -407,24 +407,24 @@ static int sunrise_read_raw(struct iio_dev *iio_dev,
 			mutex_lock(&sunrise->lock);
 			ret = sunrise_read_word(sunrise, SUNRISE_CO2_FILTERED_COMP_REG,
 						&value);
-			*val = value;
 			mutex_unlock(&sunrise->lock);
 
 			if (ret)
 				return ret;
 
+			*val = value;
 			return IIO_VAL_INT;
 
 		case IIO_TEMP:
 			mutex_lock(&sunrise->lock);
 			ret = sunrise_read_word(sunrise, SUNRISE_CHIP_TEMPERATURE_REG,
 						&value);
-			*val = value;
 			mutex_unlock(&sunrise->lock);
 
 			if (ret)
 				return ret;
 
+			*val = value;
 			return IIO_VAL_INT;
 
 		default:
-- 
2.26.3