Re: [PATCH v2] mmc: sdhci-of-dwcmshc: check bus clock enable result in the, probe() method

[Sergey Shtylyov <s.shtylyov@auroraos.dev>]

On 6/1/26 10:43 AM, Adrian Hunter wrote:

> On 29/05/2026 23:28, Sergey Shtylyov wrote:
>> In the driver's probe() method, clk_disable_unprepare() for the bus clock
>> is called on the error path even if the prior clk_prepare_enable() call has
>> failed (and the same thing happens in the remove() method as well) -- that
>> would cause the prepare/enable counter imbalance.  Also, the same problem
> 
> Doesn't clk_disable_unprepare() do nothing if clk is IS_ERR_OR_NULL()?

   Yes, I does. But my patch is not about this case, it's about the case when
clk_prepare_enable() for the bus clock fails...
 
>> can happen in the driver's suspend() method; note that the resume() method
>> does check the clk_prepare_enable()'s result -- let's be consistent and do
>> that in probe() method as well.  BTW, I don't know for sure what does the
>> bus clock control -- if it affects the register accesses, the driver will
>> likely to cause (e.g. on ARM) a kernel oops if it fails to prepare/enable
>> the bus clock in the probe() method...
>>
>> Found by Linux Verification Center (linuxtesting.org) with the Svace static
>> analysis tool.
>>
>> Fixes: e438cf49b305 ("mmc: sdhci-of-dwcmshc: add SDHCI OF Synopsys DWC MSHC driver")
>> Fixes: bccce2ec7790 ("mmc: sdhci-of-dwcmshc: add suspend/resume support")
>> Signed-off-by: Sergey Shtylyov <s.shtylyov@auroraos.dev>

[...]

MBR, Sergey