linux-kernel - Re: [PATCH] clk: Mark fwnodes when their clock provider is added

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Date:   Tue, 30 Mar 2021 09:26:19 -0700
From:   Saravana Kannan <saravanak@...gle.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Tudor Ambarus <tudor.ambarus@...rochip.com>,
        Jonathan Corbet <corbet@....net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Kevin Hilman <khilman@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        "Brown, Len" <len.brown@...el.com>, Len Brown <lenb@...nel.org>,
        Pavel Machek <pavel@....cz>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Marc Zyngier <maz@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Claudiu Beznea <claudiu.beznea@...rochip.com>,
        Linux Doc Mailing List <linux-doc@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        linux-clk <linux-clk@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Android Kernel Team <kernel-team@...roid.com>
Subject: Re: [PATCH] clk: Mark fwnodes when their clock provider is added

On Tue, Mar 30, 2021 at 8:42 AM Guenter Roeck <linux@...ck-us.net> wrote:
>
> On Wed, Feb 10, 2021 at 01:44:34PM +0200, Tudor Ambarus wrote:
> > This is a follow-up for:
> > commit 3c9ea42802a1 ("clk: Mark fwnodes when their clock provider is added/removed")
> >
> > The above commit updated the deprecated of_clk_add_provider(),
> > but missed to update the preferred of_clk_add_hw_provider().
> > Update it now.
> >
> > Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
> > Reviewed-by: Saravana Kannan <saravanak@...gle.com>
> > ---
> >  drivers/clk/clk.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> > index 27ff90eacb1f..9370e4dfecae 100644
> > --- a/drivers/clk/clk.c
> > +++ b/drivers/clk/clk.c
> > @@ -4594,6 +4594,8 @@ int of_clk_add_hw_provider(struct device_node *np,
> >       if (ret < 0)
> >               of_clk_del_provider(np);
> >
> > +     fwnode_dev_initialized(&np->fwnode, true);
> > +
>
> This causes a crash when booting raspi2 images in qemu.
>
> [   22.123618] Unable to handle kernel NULL pointer dereference at virtual address 00000028
> [   22.123830] pgd = (ptrval)
> [   22.123992] [00000028] *pgd=00000000
> [   22.124579] Internal error: Oops: 5 [#1] SMP ARM
> ...
> [   22.141624] [<c0a2f4d8>] (of_clk_add_hw_provider) from [<c0a2f54c>] (devm_of_clk_add_hw_provider+0x48/0x80)
> [   22.141819] [<c0a2f54c>] (devm_of_clk_add_hw_provider) from [<c0a43ad8>] (raspberrypi_clk_probe+0x25c/0x384)
> [   22.141976] [<c0a43ad8>] (raspberrypi_clk_probe) from [<c0c18da0>] (platform_probe+0x5c/0xb8)
> [   22.142114] [<c0c18da0>] (platform_probe) from [<c0c16654>] (really_probe+0xf0/0x39c)
> [   22.142246] [<c0c16654>] (really_probe) from [<c0c16968>] (driver_probe_device+0x68/0xc0)
> [   22.142377] [<c0c16968>] (driver_probe_device) from [<c0c14834>] (bus_for_each_drv+0x84/0xc8)...
>
> np can (and will) be NULL here. See of_clk_set_defaults().

Thanks for the report. It was reported earlier by Marek and there's a
discussion going on about it in the thread.

-Saravana