Re: [PATCH] pwm: stm32: Fix the usage of uninitialized variable in stm32_pwm_config()

[Uwe Kleine-König]

Hello,

On Thu, Oct 03, 2019 at 09:46:49PM -0700, Yizhuo wrote:
> Inside function stm32_pwm_config(), variable "psc" and " arr"
> could be uninitialized if regmap_read() returns -EINVALs.
> However, they are used later in the if statement to decide
> the return value which is potentially unsafe.
> 
> The same case happens in function stm32_pwm_detect_channels()
> with variable "ccer", but we cannot just return -EINVAL because
> the error code is not acceptable by the caller. Aslo, the variable

s/Aslo/Also/

> "ccer" in functionstm32_pwm_detect_complementary() could also be

s/functionstm32_pwm_detect_/function stm32_pwm_detect_/

> uninitialized, since stm32_pwm_detect_complementary() returns void,
> the patch is not easy.

active_channels() is also affected. Also there are calls to
regmap_update_bits which should have their return values checked.

While a patch to fix these all is not trivial it is certainly possible
and I would prefer to fix the problem completely.

Best regards
Uwe

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Pengutronix e.K.                           | Uwe Kleine-König            |
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