clk: fixed: fix double free in resource managed fixed-factor clock

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>
Link: https://lore.kernel.org/r/20210406230606.3007138-1-dmitry.baryshkov@linaro.org
Fixes: 0b9266d295ce ("clk: fixed: add devm helper for clk_hw_register_fixed_factor()")
[sboyd@kernel.org: Remove ugly cast]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c
index 4f7bf39..4e4b6d3 100644 (file)
--- a/drivers/clk/clk-fixed-factor.c
+++ b/drivers/clk/clk-fixed-factor.c
@@ -66,7 +66,14 @@ 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);
+       struct clk_fixed_factor *fix = res;
+
+       /*
+        * 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(&fix->hw);
 }
 
 static struct clk_hw *