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From: Nathan Chancellor <natechancellor@gmail.com>
To: Jonathan Cameron <jic23@kernel.org>
Cc: Hartmut Knaack <knaack.h@gmx.de>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
	linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com,
	Nick Desaulniers <ndesaulniers@google.com>,
	Nathan Chancellor <natechancellor@gmail.com>
Subject: [PATCH] iio: common: ssp_sensors: Initialize calculated_time in ssp_common_process_data
Date: Thu,  7 Mar 2019 14:45:46 -0700	[thread overview]
Message-ID: <20190307214546.9624-1-natechancellor@gmail.com> (raw)

When building with -Wsometimes-uninitialized, Clang warns:

drivers/iio/common/ssp_sensors/ssp_iio.c:95:6: warning: variable
'calculated_time' is used uninitialized whenever 'if' condition is false
[-Wsometimes-uninitialized]

While it isn't wrong, this will never be a problem because
iio_push_to_buffers_with_timestamp only uses calculated_time
on the same condition that it is assigned (when scan_timestamp
is not zero). While iio_push_to_buffers_with_timestamp is marked
as inline, Clang does inlining in the optimization stage, which
happens after the semantic analysis phase (plus inline is merely
a hint to the compiler).

Fix this by just zero initializing calculated_time.

Link: https://github.com/ClangBuiltLinux/linux/issues/394
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 drivers/iio/common/ssp_sensors/ssp_iio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/common/ssp_sensors/ssp_iio.c b/drivers/iio/common/ssp_sensors/ssp_iio.c
index 645f2e3975db..e38f704d88b7 100644
--- a/drivers/iio/common/ssp_sensors/ssp_iio.c
+++ b/drivers/iio/common/ssp_sensors/ssp_iio.c
@@ -81,7 +81,7 @@ int ssp_common_process_data(struct iio_dev *indio_dev, void *buf,
 			    unsigned int len, int64_t timestamp)
 {
 	__le32 time;
-	int64_t calculated_time;
+	int64_t calculated_time = 0;
 	struct ssp_sensor_data *spd = iio_priv(indio_dev);
 
 	if (indio_dev->scan_bytes == 0)
-- 
2.21.0


             reply	other threads:[~2019-03-07 21:46 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-07 21:45 Nathan Chancellor [this message]
2019-03-08  0:35 ` [PATCH] iio: common: ssp_sensors: Initialize calculated_time in ssp_common_process_data Nick Desaulniers
2019-03-10  9:37   ` Jonathan Cameron
2019-03-11 11:10     ` Arnd Bergmann
2019-03-11 13:50       ` Nathan Chancellor

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