On 10/01/2014 05:34 PM, Dan Carpenter wrote:
Hello Jyri Sarha,
The patch c873d14d30b8: "clk: add gpio gated clock" from Sep 5, 2014,
leads to the following static checker warning:
drivers/clk/clk-gpio-gate.c:123 clk_register_gpio_gate()
warn: passing devm_ allocated variable to kfree. 'clk_gpio'
drivers/clk/clk-gpio-gate.c
97 if (dev)
98 clk_gpio = devm_kzalloc(dev, sizeof(struct clk_gpio),
99 GFP_KERNEL);
100 else
101 clk_gpio = kzalloc(sizeof(struct clk_gpio), GFP_KERNEL);
102
103 if (!clk_gpio) {
104 clk = ERR_PTR(-ENOMEM);
105 goto clk_register_gpio_gate_err;
106 }
107
108 init.name = name;
109 init.ops = &clk_gpio_gate_ops;
110 init.flags = flags | CLK_IS_BASIC;
111 init.parent_names = (parent_name ? &parent_name : NULL);
112 init.num_parents = (parent_name ? 1 : 0);
113
114 clk_gpio->gpiod = gpiod;
115 clk_gpio->hw.init = &init;
116
117 clk = clk_register(dev, &clk_gpio->hw);
118
119 if (!IS_ERR(clk))
120 return clk;
121
122 if (!dev)
123 kfree(clk_gpio);
^^^^^^^^^^^^^^^
It's complaing about this. Obviously there is an "if (dev)" on the
allocation side. Also Smatch is supposed to be able to follow logic
like that. The other thing which may affect this, is that this is dead
code. Smatch tends to deliberately print error messages in dead code
because Smatch is confused by dead code.
Anyway, the point is that this API sucks. If it ever stops being dead
code then it's going to be a source of bugs.
Also in the kernel we tend to frown on putting in code before there is
a user for it. So lets delete all the "if (dev) " code because that
pointer is always NULL.
regards,
dan carpenter
In theory someone could call clk_register_gpio_gate() directly with a
device pointer, but well he can call kfree() then too. I'll mail a patch
in a minute.
Best regards,
Jyri
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