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7NpJlFchpaErV6WdFrXQjDAd9YwaEHucfS7SAhxIqdIqzV5vNFrMjwhB1N8MfdUJDpgyX7Zu k/Phd5aoZXNwsCRqaD2OwFZXr81zSXwE2UdPmIfTYTjeVsOAI7GZ7akCsRPK64ni0XfoXue2 XUSrUUTRimTkuMHrTYaHY3544a+GduQQLLA+avseLmjvKHxsU4zna0p0Yb4czwoJj+wSkVGQ NMDbxcY26CMPK204jhRm9RG687qq6691hbiuAtWABeAsl1AS+mdS7aP/4uOM4kFCvXYgIHxP /BoVz9CZTMEVAZVzbRKyYCLUf1wLhcHzugTiONz9fWMBLLskKvq7m1tlr61mNgY9nVwwClMU uE7i1H9r/2/UXLd+pY82zcXhFrfmKuCDmOkB5xPsOMVQJH8I0/lbqfLAqfsxSb/X1VKaP243 jzi+DzD9cvj2K6eD5j5kcKJJQactXqfJvF1Eb+OnxlB1BCLE8D1rNkPO5O742Mq3MgDmq19l +abzEL6QDAAxn9md8KwrA3RtucNh87cHlDXfUBKa7SRvBjTczDg+HEPNk2u3hrz1j3l2rliQ y1UfYx7Vk/TrdwUIJgKS8QAr8Lw9WuvY2hSqL9vEjx8VAkPWNWPwrQ== Message-ID: <8aa4acd2-dcc3-1eb8-e16f-b4e987808602@gmail.com> Date: Tue, 26 May 2020 17:42:22 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <1590460982.28324.17.camel@mtksdaap41> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200526_084225_832232_7699EA89 X-CRM114-Status: GOOD ( 22.58 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: James Liao , Nicolas Boichat , srv_heupstream@mediatek.com, Stephen Boyd , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Fan Chen , linux-mediatek@lists.infradead.org, Owen Chen , linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org Hi Weiyi, On 26/05/2020 04:43, Weiyi Lu wrote: > On Mon, 2020-05-25 at 11:08 +0200, Matthias Brugger wrote: >> >> On 25/05/2020 08:41, Weiyi Lu wrote: >>> It'd be dangerous when struct clk_core have new memebers. >>> Add the missing initial value to clk_init_data. >>> >> >> Sorry I don't really understand this commit message, can please explain. >> In any case if this is a problem, then we probably we should fix it for all drivers. >> Apart from drivers/clk/mediatek/clk-cpumux.c >> > > Actually, we were looking into an android kernel patch "ANDROID: GKI: > clk: Add support for voltage voting" [1] > > In this patch, there adds a new member struct clk_vdd_class *vdd_class; > in struct clk_init_data and struct clk_core > > And then in clk_register(...) > core->vdd_class = hw->init->vdd_class; > > In many clock APIs, it will check the core->vdd_class to select the > correct control flow. > So, if we don't assign an initial value to clk_init_data of mtk_mux > clock type, something might go wrong. And assigning an initial value > might be the easiest and good way to avoid such problem if any new clock > support added in the future. > Thanks for your explanation. You mean that as clk_init_data is on the stack it can have random values, and would lead to the fact that vdd_class is interpreted as allocated although it should be NULL. Sounds reasonable to me. You might want to resend with a better commit message. Feel free to add my Reviewed-by: Matthias Brugger Regards, Matthias > [1] https://android-review.googlesource.com/c/kernel/common/+/1278046 > >> It's a widely used pattern: >> $ git grep "struct clk_init_data init;"| wc -l >> 235 >> >> Regards, >> Matthias >> >>> Fixes: a3ae549917f1 ("clk: mediatek: Add new clkmux register API") >>> Cc: >>> Signed-off-by: Weiyi Lu >>> --- >>> drivers/clk/mediatek/clk-mux.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/clk/mediatek/clk-mux.c b/drivers/clk/mediatek/clk-mux.c >>> index 76f9cd0..14e127e 100644 >>> --- a/drivers/clk/mediatek/clk-mux.c >>> +++ b/drivers/clk/mediatek/clk-mux.c >>> @@ -160,7 +160,7 @@ struct clk *mtk_clk_register_mux(const struct mtk_mux *mux, >>> spinlock_t *lock) >>> { >>> struct mtk_clk_mux *clk_mux; >>> - struct clk_init_data init; >>> + struct clk_init_data init = {}; >>> struct clk *clk; >>> >>> clk_mux = kzalloc(sizeof(*clk_mux), GFP_KERNEL); >>> > _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek