From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Guenter Roeck <linux@roeck-us.net>
Cc: linux-arm-kernel@lists.infradead.org,
Duanqiang Wen <duanqiangwen@net-swift.com>,
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
Date: Sat, 18 May 2024 00:37:12 +0100 [thread overview]
Message-ID: <ZkfqKMqkUc/Sr7U2@shell.armlinux.org.uk> (raw)
In-Reply-To: <4ea9cc83-c7ca-47b8-8d43-dab16193108f@roeck-us.net>
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 <duanqiangwen@net-swift.com>
> > > > Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> > > > Reviewed-by: Stephen Boyd <sboyd@kernel.org>
> > >
> > > 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.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
next prev parent reply other threads:[~2024-05-17 23:37 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-15 11:47 [PATCH] clkdev: report over-sized strings when creating clkdev entries Russell King (Oracle)
2024-04-08 3:48 ` Stephen Boyd
2024-05-02 0:59 ` Stephen Boyd
2024-05-02 1:02 ` Stephen Boyd
2024-05-02 8:02 ` Russell King (Oracle)
2024-05-02 8:22 ` Russell King (Oracle)
2024-05-02 11:08 ` Russell King (Oracle)
2024-05-02 22:18 ` Stephen Boyd
2024-05-17 22:09 ` Guenter Roeck
2024-05-17 22:22 ` Russell King (Oracle)
2024-05-17 23:34 ` Guenter Roeck
2024-05-17 23:37 ` Russell King (Oracle) [this message]
2024-05-18 3:24 ` Guenter Roeck
2024-05-18 7:01 ` Russell King (Oracle)
2024-05-22 6:53 ` Linux regression tracking (Thorsten Leemhuis)
2024-05-22 9:34 ` Russell King (Oracle)
2024-05-22 9:37 ` Russell King (Oracle)
2024-05-22 21:32 ` Guenter Roeck
2024-05-18 13:44 ` Guenter Roeck
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