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From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Stephen Boyd <sboyd@kernel.org>,
	Michael Turquette <mturquette@baylibre.com>
Cc: linux-arm-msm@vger.kernel.org, linux-clk@vger.kernel.org,
	dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org,
	Rob Clark <robdclark@chromium.org>,
	Daniel Palmer <daniel@0x0f.com>
Subject: [PATCH] clk: fixed: fix double free in resource managed fixed-factor clock
Date: Wed,  7 Apr 2021 02:06:06 +0300
Message-ID: <20210406230606.3007138-1-dmitry.baryshkov@linaro.org> (raw)

devm_clk_hw_register_fixed_factor_release(), the release function for
the devm_clk_hw_register_fixed_factor(), calls
clk_hw_unregister_fixed_factor(), which will kfree() the clock. However
after that the devres functions will also kfree the allocated data,
resulting in double free/memory corruption. Just call
clk_hw_unregister() instead, leaving kfree() to devres code.

Reported-by: Rob Clark <robdclark@chromium.org>
Cc: Daniel Palmer <daniel@0x0f.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---

Stephen, this fix affects the DSI PHY rework. Do we have a chance of
getting it into 5.12, otherwise there will be a cross-dependency between
msm-next and clk-next.

---
 drivers/clk/clk-fixed-factor.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c
index 4f7bf3929d6d..390c16f321a6 100644
--- a/drivers/clk/clk-fixed-factor.c
+++ b/drivers/clk/clk-fixed-factor.c
@@ -66,7 +66,12 @@ EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
 
 static void devm_clk_hw_register_fixed_factor_release(struct device *dev, void *res)
 {
-	clk_hw_unregister_fixed_factor(&((struct clk_fixed_factor *)res)->hw);
+	/*
+	 * We can not use clk_hw_unregister_fixed_factor, since it will kfree()
+	 * the hw, resulting in double free. Just unregister the hw and let
+	 * devres code kfree() it.
+	 */
+	clk_hw_unregister(&((struct clk_fixed_factor *)res)->hw);
 }
 
 static struct clk_hw *
-- 
2.30.2


             reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-06 23:06 Dmitry Baryshkov [this message]
2021-04-07  9:00 ` Dmitry Baryshkov
2021-04-07 11:38 ` Daniel Palmer
2021-04-07 22:41 ` Stephen Boyd
2021-04-07 22:57   ` Dmitry Baryshkov
     [not found]     ` <161783803315.3790633.10829887417379757624@swboyd.mtv.corp.google.com>
2021-04-08  0:52       ` Dmitry Baryshkov
2021-04-08  7:32         ` Stephen Boyd
2021-04-07 23:01 ` Stephen Boyd

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