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Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:57026) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1s8E4F-0008BX-2v; Sat, 18 May 2024 08:01:21 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1s8E4B-0002JK-0a; Sat, 18 May 2024 08:01:15 +0100 Date: Sat, 18 May 2024 08:01:14 +0100 From: "Russell King (Oracle)" To: Guenter Roeck Cc: linux-arm-kernel@lists.infradead.org, Duanqiang Wen , mturquette@baylibre.com, sboyd@kernel.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] clkdev: report over-sized strings when creating clkdev entries Message-ID: References: <7eda7621-0dde-4153-89e4-172e4c095d01@roeck-us.net> <4ea9cc83-c7ca-47b8-8d43-dab16193108f@roeck-us.net> <646bd149-f29a-4c91-ab00-4f6d2fce23fd@roeck-us.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <646bd149-f29a-4c91-ab00-4f6d2fce23fd@roeck-us.net> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240518_000131_391749_466B2C26 X-CRM114-Status: GOOD ( 37.95 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, May 17, 2024 at 08:24:19PM -0700, Guenter Roeck wrote: > On 5/17/24 16:37, Russell King (Oracle) wrote: > > On Fri, May 17, 2024 at 04:34:06PM -0700, Guenter Roeck wrote: > > > On 5/17/24 15:22, Russell King (Oracle) wrote: > > > > On Fri, May 17, 2024 at 03:09:12PM -0700, Guenter Roeck wrote: > > > > > Hi, > > > > > > > > > > On Fri, Mar 15, 2024 at 11:47:55AM +0000, Russell King (Oracle) wrote: > > > > > > Report an error when an attempt to register a clkdev entry results in a > > > > > > truncated string so the problem can be easily spotted. > > > > > > > > > > > > Reported by: Duanqiang Wen > > > > > > Signed-off-by: Russell King (Oracle) > > > > > > Reviewed-by: Stephen Boyd > > > > > > > > > > With this patch in the mainline kernel, I get > > > > > > > > > > 10000000.clock-controller:corepll: device ID is greater than 24 > > > > > sifive-clk-prci 10000000.clock-controller: Failed to register clkdev for corepll: -12 > > > > > sifive-clk-prci 10000000.clock-controller: could not register clocks: -12 > > > > > sifive-clk-prci 10000000.clock-controller: probe with driver sifive-clk-prci failed with error -12 > > > > > ... > > > > > platform 10060000.gpio: deferred probe pending: platform: supplier 10000000.clock-controller not ready > > > > > platform 10010000.serial: deferred probe pending: platform: supplier 10000000.clock-controller not ready > > > > > platform 10011000.serial: deferred probe pending: platform: supplier 10000000.clock-controller not ready > > > > > platform 10040000.spi: deferred probe pending: platform: supplier 10000000.clock-controller not ready > > > > > platform 10050000.spi: deferred probe pending: platform: supplier 10000000.clock-controller not ready > > > > > platform 10090000.ethernet: deferred probe pending: platform: supplier 10000000.clock-controller not ready > > > > > > > > > > when trying to boot sifive_u in qemu. > > > > > > > > > > Apparently, "10000000.clock-controller" is too long. Any suggestion on > > > > > how to solve the problem ? I guess using dev_name(dev) as dev_id parameter > > > > > for clk_hw_register_clkdev() is not or no longer a good idea. > > > > > What else should be used instead ? > > > > > > > > It was *never* a good idea. clkdev uses a fixed buffer size of 20 > > > > characters including the NUL character, and "10000000.clock-controller" > > > > would have been silently truncated to "10000000.clock-cont", and thus > > > > > > > > if (!dev_id || strcmp(p->dev_id, dev_id)) > > > > > > > > would never have matched. > > > > > > > > We need to think about (a) whether your use of clk_hw_register_clkdev() > > > > is still appropriate, and (b) whether we need to increase the size of > > > > the strings. > > > > > > > > > > It isn't _my_ use, really. I only run a variety of boot tests with qemu. > > > I expect we'll see reports from others trying to boot the mainline kernel > > > on real sifive_u hardware or other hardware using the same driver or other > > > drivers using dev_name() as dev_id parameter. Coccinelle finds the > > > following callers: > > > > Using dev_name() is not an issue. It's when dev_name() exceeds 19 > > characters that it becomes an issue (and always has been an issue > > due to the truncation.) clk_get(dev, ...) uses dev_name(dev) to match > > against its entry in the table. > > > > As I say, dev_name() itself is not an issue. The length used for the > > name is. > > > > Maybe, but the existence of best_dev_name() suggests that this has been seen > before and that, as you mentioned, it is not a good idea. Anyway, the patch > below fixes the problem for me. I don't know if it is acceptable / correct, > so it might serve as guidance for others when fixing the problem for real. I get the impression that there's a communication problem here, so I'm not going to continue replying. Thanks. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel