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[83.24.25.156]) by smtp.gmail.com with ESMTPSA id d2sm8207572lfg.16.2018.12.28.08.52.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 28 Dec 2018 08:52:32 -0800 (PST) Subject: Re: [PATCH] leds: fix a missing check of return value of lp55xx_read To: Kangjie Lu Cc: pakki001@umn.edu, Pavel Machek , linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org References: <20181226041823.73950-1-kjlu@umn.edu> From: Jacek Anaszewski Message-ID: <333a5518-ad9d-868c-a5b6-731e10c053ea@gmail.com> Date: Fri, 28 Dec 2018 17:52:27 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: <20181226041823.73950-1-kjlu@umn.edu> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Kangjie, Thank you for the patch. On 12/26/18 5:18 AM, Kangjie Lu wrote: > When lp55xx_read() fails, "status" is an uninitialized variable and thus > may contain random value; using it leads to undefined behaviors. > > The fix inserts a check for the return value of lp55xx_read: if it > fails, returns with its error code. > > Signed-off-by: Kangjie Lu > --- > drivers/leds/leds-lp5523.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/leds/leds-lp5523.c b/drivers/leds/leds-lp5523.c > index a2e74feee2b2..fd64df5a57a5 100644 > --- a/drivers/leds/leds-lp5523.c > +++ b/drivers/leds/leds-lp5523.c > @@ -318,7 +318,9 @@ static int lp5523_init_program_engine(struct lp55xx_chip *chip) > > /* Let the programs run for couple of ms and check the engine status */ > usleep_range(3000, 6000); > - lp55xx_read(chip, LP5523_REG_STATUS, &status); > + ret = lp55xx_read(chip, LP5523_REG_STATUS, &status); > + if (ret) > + return ret; > status &= LP5523_ENG_STATUS_MASK; > > if (status != LP5523_ENG_STATUS_MASK) { > Applied to fixes-for-4.21 branch of linux-leds.git. -- Best regards, Jacek Anaszewski