During several error paths in the function
regulator_set_voltage_unlocked() the value of 'ret' can take on negative
error values. However, in calls that go through the 'goto out' statement,
this return value is lost and return 0 is used instead, indicating a
'pass'.
There are several cases where this function should legitimately return a
fail instead of a pass: one such case includes constraints check during
voltage selection in the call to regulator_check_voltage(), which can
have -EINVAL for the case when an unsupported voltage is incorrectly
requested. In that case, -22 is expected as the return value, not 0.
Fixes: 9243a195be7a ("regulator: core: Change voltage setting path")
Signed-off-by: Steve Twiss <[email protected]>
---
drivers/regulator/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 68473d0..caf8743 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -3326,7 +3326,7 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
goto out2;
out:
- return 0;
+ return ret;
out2:
voltage->min_uV = old_min_uV;
voltage->max_uV = old_max_uV;
--
1.9.3
18.03.2019 18:32, Steve Twiss пишет:
> During several error paths in the function
> regulator_set_voltage_unlocked() the value of 'ret' can take on negative
> error values. However, in calls that go through the 'goto out' statement,
> this return value is lost and return 0 is used instead, indicating a
> 'pass'.
>
> There are several cases where this function should legitimately return a
> fail instead of a pass: one such case includes constraints check during
> voltage selection in the call to regulator_check_voltage(), which can
> have -EINVAL for the case when an unsupported voltage is incorrectly
> requested. In that case, -22 is expected as the return value, not 0.
>
> Fixes: 9243a195be7a ("regulator: core: Change voltage setting path")
> Signed-off-by: Steve Twiss <[email protected]>
> ---
> drivers/regulator/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> index 68473d0..caf8743 100644
> --- a/drivers/regulator/core.c
> +++ b/drivers/regulator/core.c
> @@ -3326,7 +3326,7 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
> goto out2;
>
> out:
> - return 0;
> + return ret;
> out2:
> voltage->min_uV = old_min_uV;
> voltage->max_uV = old_max_uV;
>
Looks like a good catch.
Probably will be a bit better to write this as:
/* for not coupled regulators this will just set the voltage */
ret = regulator_balance_voltage(rdev, state);
- if (ret < 0)
- goto out2;
-
+ if (ret < 0) {
+ voltage->min_uV = old_min_uV;
+ voltage->max_uV = old_max_uV;
+ }
out:
- return 0;
-out2:
- voltage->min_uV = old_min_uV;
- voltage->max_uV = old_max_uV;
-
return ret;
}
18.03.2019 19:03, Dmitry Osipenko пишет:
> 18.03.2019 18:32, Steve Twiss пишет:
>> During several error paths in the function
>> regulator_set_voltage_unlocked() the value of 'ret' can take on negative
>> error values. However, in calls that go through the 'goto out' statement,
>> this return value is lost and return 0 is used instead, indicating a
>> 'pass'.
>>
>> There are several cases where this function should legitimately return a
>> fail instead of a pass: one such case includes constraints check during
>> voltage selection in the call to regulator_check_voltage(), which can
>> have -EINVAL for the case when an unsupported voltage is incorrectly
>> requested. In that case, -22 is expected as the return value, not 0.
>>
>> Fixes: 9243a195be7a ("regulator: core: Change voltage setting path")
>> Signed-off-by: Steve Twiss <[email protected]>
>> ---
>> drivers/regulator/core.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
>> index 68473d0..caf8743 100644
>> --- a/drivers/regulator/core.c
>> +++ b/drivers/regulator/core.c
>> @@ -3326,7 +3326,7 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
>> goto out2;
>>
>> out:
>> - return 0;
>> + return ret;
>> out2:
>> voltage->min_uV = old_min_uV;
>> voltage->max_uV = old_max_uV;
>>
>
> Looks like a good catch.
>
> Probably will be a bit better to write this as:
>
> /* for not coupled regulators this will just set the voltage */
> ret = regulator_balance_voltage(rdev, state);
> - if (ret < 0)
> - goto out2;
> -
> + if (ret < 0) {
> + voltage->min_uV = old_min_uV;
> + voltage->max_uV = old_max_uV;
> + }
> out:
> - return 0;
> -out2:
> - voltage->min_uV = old_min_uV;
> - voltage->max_uV = old_max_uV;
> -
> return ret;
> }
>
Also, probably won't hurt to add a stable tag "Cc: stable <[email protected]>" to get the fix backported.
Hi Dmitry,
Thanks,
On 18 March 2019 16:03, Dmitry Osipenko wrote:
> Subject: Re: [PATCH] regulator: core: fix error path for
> regulator_set_voltage_unlocked
>
> 18.03.2019 18:32, Steve Twiss пишет:
> > During several error paths in the function
> > regulator_set_voltage_unlocked() the value of 'ret' can take on negative
> > error values. However, in calls that go through the 'goto out' statement,
> > this return value is lost and return 0 is used instead, indicating a
> > 'pass'.
> >
> > There are several cases where this function should legitimately return a
> > fail instead of a pass: one such case includes constraints check during
> > voltage selection in the call to regulator_check_voltage(), which can
> > have -EINVAL for the case when an unsupported voltage is incorrectly
> > requested. In that case, -22 is expected as the return value, not 0.
> >
> > Fixes: 9243a195be7a ("regulator: core: Change voltage setting path")
> > Signed-off-by: Steve Twiss <[email protected]>
> > ---
> > drivers/regulator/core.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> > index 68473d0..caf8743 100644
> > --- a/drivers/regulator/core.c
> > +++ b/drivers/regulator/core.c
> > @@ -3326,7 +3326,7 @@ static int regulator_set_voltage_unlocked(struct
> regulator *regulator,
> > goto out2;
> >
> > out:
> > - return 0;
> > + return ret;
> > out2:
> > voltage->min_uV = old_min_uV;
> > voltage->max_uV = old_max_uV;
> >
>
> Looks like a good catch.
>
> Probably will be a bit better to write this as:
>
> /* for not coupled regulators this will just set the voltage */
> ret = regulator_balance_voltage(rdev, state);
> - if (ret < 0)
> - goto out2;
> -
> + if (ret < 0) {
> + voltage->min_uV = old_min_uV;
> + voltage->max_uV = old_max_uV;
> + }
> out:
> - return 0;
> -out2:
> - voltage->min_uV = old_min_uV;
> - voltage->max_uV = old_max_uV;
> -
> return ret;
> }
I've just had a very similar conversation with Adam Thomson who sits near me and also
said the two gotos make it look confusing.
Honestly -- I wasn't convinced because it looked obvious to me, but you are the second
person to say it ..
CC: Adam Thomson
So, ok. Agreed. :)
I'll make the change and resend.
Regards,
Steve