Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1201519

Re: [RFC PATCH] regulator: Fix recursive mutex lockdep warning

Show all headers | View raw

Thanks Krzysztof

On 06/08/15 02:39, Krzysztof Kozlowski wrote:
>> --- a/drivers/regulator/core.c
>> >+++ b/drivers/regulator/core.c
>> >@@ -2919,7 +2919,7 @@ static int _regulator_get_voltage(struct regulator_dev *rdev)
>> >         } else if (rdev->desc->fixed_uV && (rdev->desc->n_voltages == 1)) {
>> >                 ret = rdev->desc->fixed_uV;
>> >         } else if (rdev->supply) {
>> >-               ret = regulator_get_voltage(rdev->supply);
>> >+               ret = _regulator_get_voltage(rdev->supply->rdev);
> Is the 'rdev' and 'rdev->supply' same regulators? If not then you are
> just hiding false warning by removing locks thus introducing real
> issue...
They are the not the same regulators, and hence they are not locking the 
same mutex, looks like this is a false positive warning from lockdep. I 
can't think of any use case which could result in ABBA type lockup too, 
so we can ignore this patch for now.

Not sure why did the lockdep think that this is same lock :-)

--srini
>
> Best regards,
> Krzysztof
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[RFC PATCH] regulator: Fix recursive mutex lockdep warning Srinivas Kandagatla <srinivas.kandagatla@linaro.org> - 2015-08-05 18:10 +0200
  Re: [RFC PATCH] regulator: Fix recursive mutex lockdep warning Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2015-08-06 03:40 +0200
    Re: [RFC PATCH] regulator: Fix recursive mutex lockdep warning Srinivas Kandagatla <srinivas.kandagatla@linaro.org> - 2015-08-06 09:40 +0200
      Re: [RFC PATCH] regulator: Fix recursive mutex lockdep warning Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2015-08-06 09:40 +0200
        Re: [RFC PATCH] regulator: Fix recursive mutex lockdep warning Krzysztof Kozlowski <k.kozlowski@samsung.com> - 2015-08-06 10:00 +0200
  Re: [RFC PATCH] regulator: Fix recursive mutex lockdep warning Mark Brown <broonie@kernel.org> - 2015-08-06 11:50 +0200
    Re: [RFC PATCH] regulator: Fix recursive mutex lockdep warning Srinivas Kandagatla <srinivas.kandagatla@linaro.org> - 2015-08-06 13:10 +0200
      Re: [RFC PATCH] regulator: Fix recursive mutex lockdep warning Srinivas Kandagatla <srinivas.kandagatla@linaro.org> - 2015-08-06 13:50 +0200
        Re: [RFC PATCH] regulator: Fix recursive mutex lockdep warning Mark Brown <broonie@kernel.org> - 2015-08-07 16:20 +0200
      Re: [RFC PATCH] regulator: Fix recursive mutex lockdep warning Mark Brown <broonie@kernel.org> - 2015-08-06 13:50 +0200

csiph-web