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

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Message-Id: <20240623-sunxi-ng_fix_common_probe-v1-1-7c97e32824a1@oltmanns.dev>
Date: Sun, 23 Jun 2024 10:45:58 +0200
From: Frank Oltmanns <frank@...manns.dev>
To: Michael Turquette <mturquette@...libre.com>, 
 Stephen Boyd <sboyd@...nel.org>, Chen-Yu Tsai <wens@...e.org>, 
 Jernej Skrabec <jernej.skrabec@...il.com>, 
 Samuel Holland <samuel@...lland.org>, Maxime Ripard <mripard@...nel.org>
Cc: Måns Rullgård <mans@...sr.com>, 
 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, 
 Frank Oltmanns <frank@...manns.dev>
Subject: [PATCH] clk: sunxi-ng: common: Don't call hw_to_ccu_common on hw
 without common

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"

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>