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Thu, 06 Jul 2023 05:29:13 -0700 (PDT) Received: from [192.168.1.172] ([93.5.22.158]) by smtp.gmail.com with ESMTPSA id f14-20020adff44e000000b003142ea7a661sm1799342wrp.21.2023.07.06.05.29.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 06 Jul 2023 05:29:12 -0700 (PDT) Message-ID: <55c3a448-e6c6-5e04-2cee-b2a18f0033e3@baylibre.com> Date: Thu, 6 Jul 2023 14:29:11 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH] pwm: mtk_disp: fix disp_pwm coverity issue Content-Language: en-US To: Shuijing Li , thierry.reding@gmail.com, u.kleine-koenig@pengutronix.de, matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com Cc: devicetree@vger.kernel.org, linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Project_Global_Chrome_Upstream_Group@mediatek.com, jitao.shi@mediatek.com References: <20230706100454.28998-1-shuijing.li@mediatek.com> From: Alexandre Mergnat In-Reply-To: <20230706100454.28998-1-shuijing.li@mediatek.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230706_052915_599740_B6807803 X-CRM114-Status: GOOD ( 17.46 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On 06/07/2023 12:04, Shuijing Li wrote: > There is a coverity issue in the original mtk_disp_pwm_get_state() > function. In function call DIV64_U64_ROUND_UP, division by expression > Which may be zero has undefined behavior. > Fix this accordingly. > > Signed-off-by: Shuijing Li > --- > drivers/pwm/pwm-mtk-disp.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c > index 79e321e96f56..ca00058a6ef4 100644 > --- a/drivers/pwm/pwm-mtk-disp.c > +++ b/drivers/pwm/pwm-mtk-disp.c > @@ -196,6 +196,14 @@ static int mtk_disp_pwm_get_state(struct pwm_chip *chip, > return err; > } > > + rate = clk_get_rate(mdp->clk_main); > + if (rate <= 0) { > + dev_err(chip->dev, "Can't get rate: %pe\n", ERR_PTR(rate)); > + clk_disable_unprepare(mdp->clk_mm); > + clk_disable_unprepare(mdp->clk_main); > + return err; > + } > + > /* > * Apply DISP_PWM_DEBUG settings to choose whether to enable or disable > * registers double buffer and manual commit to working register before > @@ -206,7 +214,6 @@ static int mtk_disp_pwm_get_state(struct pwm_chip *chip, > mdp->data->bls_debug_mask, > mdp->data->bls_debug_mask); > > - rate = clk_get_rate(mdp->clk_main); > con0 = readl(mdp->base + mdp->data->con0); > con1 = readl(mdp->base + mdp->data->con1); > pwm_en = readl(mdp->base + DISP_PWM_EN); IMHO, it should be done int the function `mtk_disp_pwm_apply` too. Do you agree ? -- Regards, Alexandre