linux-kernel - [PATCH v2 1/3] clk: Don't dereference parent clock if is NULL

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Date:	Thu, 12 Feb 2015 14:58:28 +0100
From:	Javier Martinez Canillas <javier.martinez@...labora.co.uk>
To:	Mike Turquette <mturquette@...aro.org>
Cc:	Stephen Boyd <sboyd@...eaurora.org>,
	Tomeu Vizoso <tomeu.vizoso@...labora.com>,
	Emilio López <emilio@...pez.com.ar>,
	Peter De Schrijver <pdeschrijver@...dia.com>,
	Robert Jarzmik <robert.jarzmik@...e.fr>,
	Giuseppe Cavallaro <peppe.cavallaro@...com>,
	linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
	Javier Martinez Canillas <javier.martinez@...labora.co.uk>
Subject: [PATCH v2 1/3] clk: Don't dereference parent clock if is NULL

The clock passed as an argument to clk_mux_determine_rate_flags()
has the CLK_SET_RATE_PARENT flag set but it has no parent, then a
NULL pointer will tried to be dereferenced.

This shouldn't happen since setting that flag for a clock with no
parent is a bug but the core should be robust to handle that case.

Fixes: 035a61c314eb3 ("clk: Make clk API return per-user struct clk instances")
Signed-off-by: Javier Martinez Canillas <javier.martinez@...labora.co.uk>
---

Changes since v2:
 - Pass NULL struct clk_hw argument to __clk_determine_rate() if parent is NULL.
   suggested by Stephen Boyd.
---
 drivers/clk/clk.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 7f53166af5e6..5941af7b4665 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -800,8 +800,8 @@ clk_mux_determine_rate_flags(struct clk_hw *hw, unsigned long rate,
 	if (core->flags & CLK_SET_RATE_NO_REPARENT) {
 		parent = core->parent;
 		if (core->flags & CLK_SET_RATE_PARENT)
-			best = __clk_determine_rate(parent->hw, rate,
-						    min_rate, max_rate);
+			best = __clk_determine_rate(parent ? parent->hw : NULL,
+						    rate, min_rate, max_rate);
 		else if (parent)
 			best = clk_core_get_rate_nolock(parent);
 		else
-- 
2.1.3

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