linux-kernel - Re: [PATCH] clk: sunxi-ng: common: Don't call hw_to_ccu

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Date: Sat, 29 Jun 2024 14:40:11 +0800
From: Chen-Yu Tsai <wens@...e.org>
To: Måns Rullgård <mans@...sr.com>
Cc: Frank Oltmanns <frank@...manns.dev>, Michael Turquette <mturquette@...libre.com>, 
	Stephen Boyd <sboyd@...nel.org>, Jernej Skrabec <jernej.skrabec@...il.com>, 
	Samuel Holland <samuel@...lland.org>, Maxime Ripard <mripard@...nel.org>, linux-clk@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev, 
	linux-kernel@...r.kernel.org, 
	"Robert J. Pafford" <pafford.9@...keyemail.osu.edu>, stable@...r.kernel.org
Subject: Re: [PATCH] clk: sunxi-ng: common: Don't call hw_to_ccu_common on hw
 without common

On Thu, Jun 27, 2024 at 7:39 PM Måns Rullgård <mans@...sr.com> wrote:
>
> Frank Oltmanns <frank@...manns.dev> writes:
>
> > In order to set the rate range of a hw sunxi_ccu_probe calls
> > hw_to_ccu_common() assuming all entries in desc->ccu_clks are contained
> > in a ccu_common struct. This assumption is incorrect and, in
> > consequence, causes invalid pointer de-references.
> >
> > Remove the faulty call. Instead, add one more loop that iterates over
> > the ccu_clks and sets the rate range, if required.
> >
> > Fixes: b914ec33b391 ("clk: sunxi-ng: common: Support minimum and maximum rate")
> > Reported-by: Robert J. Pafford <pafford.9@...keyemail.osu.edu>
> > Closes: https://lore.kernel.org/lkml/DM6PR01MB58047C810DDD5D0AE397CADFF7C22@DM6PR01MB5804.prod.exchangelabs.com/
> > Cc: stable@...r.kernel.org
> > Signed-off-by: Frank Oltmanns <frank@...manns.dev>
> > ---
> > Robert, could you please test if this fixes the issue you reported.
> >
> > I'm CC'ing Måns here, because he observed some strange behavior [1] with
> > the original patch. Is it possible for you to look into if this patch
> > fixes your issue without the need for the following (seemingly
> > unrelated) patches:
> >       cedb7dd193f6 "drm/sun4i: hdmi: Convert encoder to atomic"
> >       9ca6bc246035 "drm/sun4i: hdmi: Move mode_set into enable"
>
> This does indeed fix it.  6.9 is still broken, though, but that's
> probably for other reasons.

Can I take that as a Tested-by?

> > Thanks,
> >   Frank
> >
> > [1]: https://lore.kernel.org/lkml/yw1xo78z8ez0.fsf@mansr.com/
> > ---
> >  drivers/clk/sunxi-ng/ccu_common.c | 18 ++++++++++++------
> >  1 file changed, 12 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/clk/sunxi-ng/ccu_common.c b/drivers/clk/sunxi-ng/ccu_common.c
> > index ac0091b4ce24..be375ce0149c 100644
> > --- a/drivers/clk/sunxi-ng/ccu_common.c
> > +++ b/drivers/clk/sunxi-ng/ccu_common.c
> > @@ -132,7 +132,6 @@ static int sunxi_ccu_probe(struct sunxi_ccu *ccu, struct device *dev,
> >
> >       for (i = 0; i < desc->hw_clks->num ; i++) {
> >               struct clk_hw *hw = desc->hw_clks->hws[i];
> > -             struct ccu_common *common = hw_to_ccu_common(hw);
> >               const char *name;
> >
> >               if (!hw)
> > @@ -147,14 +146,21 @@ static int sunxi_ccu_probe(struct sunxi_ccu *ccu, struct device *dev,
> >                       pr_err("Couldn't register clock %d - %s\n", i, name);
> >                       goto err_clk_unreg;
> >               }
> > +     }
> > +
> > +     for (i = 0; i < desc->num_ccu_clks; i++) {
> > +             struct ccu_common *cclk = desc->ccu_clks[i];
> > +
> > +             if (!cclk)
> > +                     continue;
> >
> > -             if (common->max_rate)
> > -                     clk_hw_set_rate_range(hw, common->min_rate,
> > -                                           common->max_rate);
> > +             if (cclk->max_rate)
> > +                     clk_hw_set_rate_range(&cclk->hw, cclk->min_rate,
> > +                                           cclk->max_rate);
> >               else
> > -                     WARN(common->min_rate,
> > +                     WARN(cclk->min_rate,
> >                            "No max_rate, ignoring min_rate of clock %d - %s\n",
> > -                          i, name);
> > +                          i, clk_hw_get_name(&cclk->hw));
> >       }
> >
> >       ret = of_clk_add_hw_provider(node, of_clk_hw_onecell_get,
> >
> > ---
> > base-commit: 2607133196c35f31892ee199ce7ffa717bea4ad1
> > change-id: 20240622-sunxi-ng_fix_common_probe-5677c3e487fc
> >
> > Best regards,
> > --
> >
> > Frank Oltmanns <frank@...manns.dev>
> >
>
> --
> Måns Rullgård