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([2409:4080:204:a537:70f5:9c3d:61d0:62b9]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-22ac7b62973sm33616095ad.24.2025.04.10.10.37.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 10 Apr 2025 10:37:49 -0700 (PDT) Message-ID: Date: Thu, 10 Apr 2025 23:07:43 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] iio: addac: ad74115: Fix use of uninitialized variable rate To: David Lechner , cosmin.tanislav@analog.com, lars@metafoo.de, Michael.Hennerich@analog.com, jic23@kernel.org Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250409202945.205088-1-purvayeshi550@gmail.com> <1254dfd7-e872-4c65-bd17-8015e1b2eba4@baylibre.com> Content-Language: en-US From: Purva Yeshi In-Reply-To: <1254dfd7-e872-4c65-bd17-8015e1b2eba4@baylibre.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 10/04/25 20:21, David Lechner wrote: > On 4/9/25 3:29 PM, Purva Yeshi wrote: >> Fix Smatch-detected error: >> drivers/iio/addac/ad74115.c:823 _ad74115_get_adc_code() error: >> uninitialized symbol 'rate'. >> >> The variable rate was declared but not given any value before being used >> in a division. If the code reached that point without setting rate, it >> would cause unpredictable behavior. >> >> Declare and initialize 'rate' to zero inside the 'else' block where it is >> used. This ensures 'rate' is always initialized before being passed to >> DIV_ROUND_CLOSEST. >> >> Signed-off-by: Purva Yeshi >> --- >> drivers/iio/addac/ad74115.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/iio/addac/ad74115.c b/drivers/iio/addac/ad74115.c >> index a7e480f2472d..26770c68e5fa 100644 >> --- a/drivers/iio/addac/ad74115.c >> +++ b/drivers/iio/addac/ad74115.c >> @@ -814,7 +814,7 @@ static int _ad74115_get_adc_code(struct ad74115_state *st, >> return -ETIMEDOUT; >> } else { >> unsigned int regval, wait_time; >> - int rate; >> + int rate = 0; >> >> ret = ad74115_get_adc_rate(st, channel, &rate); >> if (ret < 0) > > I don't see how rate could be used uninitialized since we are > returning the error if ad74115_get_adc_rate() fails. > > Also, initializing to 0 would then cause a divide by 0 error > if that value was actually used later in the code. Hi, Thank you for the review and explanation. Understood — since there's a risk of misuse later (like divide-by-zero), it's best to leave it as is. Best regards, Purva > >