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* [RESEND PATCH v2] power_supply: power_supply_read_temp only if use_cnt > 0
@ 2016-06-06 16:56 Rhyland Klein
  2016-06-07  7:23 ` Krzysztof Kozlowski
  0 siblings, 1 reply; 3+ messages in thread
From: Rhyland Klein @ 2016-06-06 16:56 UTC (permalink / raw)
  To: Sebastian Reichel, Dmitry Eremin-Solenikov, David Woodhouse
  Cc: linux-pm, linux-kernel, Jon Hunter, Krzysztof Kozlowski,
	Rhyland Klein, stable

Add check to power_supply_read_temp() to only use the power_supply
get_property() callback if the use_cnt is > 0. The use_cnt will
be incremented at the end of __power_supply_register, so this will
block to case where get_property can be called before the supply
is fully registered. This fixes the issue show in the stack below:

[    1.452598] power_supply_read_temp+0x78/0x80
[    1.458680] thermal_zone_get_temp+0x5c/0x11c
[    1.464765] thermal_zone_device_update+0x34/0xb4
[    1.471195] thermal_zone_device_register+0x87c/0x8cc
[    1.477974] __power_supply_register+0x364/0x424
[    1.484317] power_supply_register_no_ws+0x10/0x18
[    1.490833] bq27xxx_battery_setup+0x10c/0x164
[    1.497003] bq27xxx_battery_i2c_probe+0xd0/0x1b0
[    1.503435] i2c_device_probe+0x174/0x240
[    1.509172] driver_probe_device+0x1fc/0x29c
[    1.515167] __driver_attach+0xa4/0xa8
[    1.520643] bus_for_each_dev+0x58/0x98
[    1.526204] driver_attach+0x20/0x28
[    1.531505] bus_add_driver+0x1c8/0x22c
[    1.537067] driver_register+0x68/0x108
[    1.542630] i2c_register_driver+0x38/0x7c
[    1.548457] bq27xxx_battery_i2c_driver_init+0x18/0x20
[    1.555321] do_one_initcall+0x38/0x12c
[    1.560886] kernel_init_freeable+0x148/0x1ec
[    1.566972] kernel_init+0x10/0xfc
[    1.572101] ret_from_fork+0x10/0x40

Cc: stable@vger.kernel.org
Signed-off-by: Rhyland Klein <rklein@nvidia.com>
---
v2:
 - Added cc stable
 - changed return to -EAGAIN in case of use_cnt < 1
 - Removed WARNING
 - return value check added in additional patch:
  "thermal: helpers: Check return value of get_temp"

 drivers/power/power_supply_core.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index 456987c88baa..bbd80631f31e 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -561,11 +561,15 @@ static int power_supply_read_temp(struct thermal_zone_device *tzd,
 {
 	struct power_supply *psy;
 	union power_supply_propval val;
-	int ret;
+	int ret = -EAGAIN;
 
 	WARN_ON(tzd == NULL);
+
 	psy = tzd->devdata;
-	ret = psy->desc->get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);
+
+	if (atomic_read(&psy->use_cnt) > 0)
+		ret = psy->desc->get_property(psy, POWER_SUPPLY_PROP_TEMP,
+					      &val);
 
 	/* Convert tenths of degree Celsius to milli degree Celsius. */
 	if (!ret)
-- 
1.9.1

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [RESEND PATCH v2] power_supply: power_supply_read_temp only if use_cnt > 0
  2016-06-06 16:56 [RESEND PATCH v2] power_supply: power_supply_read_temp only if use_cnt > 0 Rhyland Klein
@ 2016-06-07  7:23 ` Krzysztof Kozlowski
  2016-06-07 16:45   ` Rhyland Klein
  0 siblings, 1 reply; 3+ messages in thread
From: Krzysztof Kozlowski @ 2016-06-07  7:23 UTC (permalink / raw)
  To: Rhyland Klein, Sebastian Reichel, Dmitry Eremin-Solenikov,
	David Woodhouse
  Cc: linux-pm, linux-kernel, Jon Hunter, stable

On 06/06/2016 06:56 PM, Rhyland Klein wrote:
> Add check to power_supply_read_temp() to only use the power_supply
> get_property() callback if the use_cnt is > 0. The use_cnt will
> be incremented at the end of __power_supply_register, so this will
> block to case where get_property can be called before the supply
> is fully registered. This fixes the issue show in the stack below:
> 
> [    1.452598] power_supply_read_temp+0x78/0x80
> [    1.458680] thermal_zone_get_temp+0x5c/0x11c
> [    1.464765] thermal_zone_device_update+0x34/0xb4
> [    1.471195] thermal_zone_device_register+0x87c/0x8cc
> [    1.477974] __power_supply_register+0x364/0x424
> [    1.484317] power_supply_register_no_ws+0x10/0x18
> [    1.490833] bq27xxx_battery_setup+0x10c/0x164
> [    1.497003] bq27xxx_battery_i2c_probe+0xd0/0x1b0
> [    1.503435] i2c_device_probe+0x174/0x240
> [    1.509172] driver_probe_device+0x1fc/0x29c
> [    1.515167] __driver_attach+0xa4/0xa8
> [    1.520643] bus_for_each_dev+0x58/0x98
> [    1.526204] driver_attach+0x20/0x28
> [    1.531505] bus_add_driver+0x1c8/0x22c
> [    1.537067] driver_register+0x68/0x108
> [    1.542630] i2c_register_driver+0x38/0x7c
> [    1.548457] bq27xxx_battery_i2c_driver_init+0x18/0x20
> [    1.555321] do_one_initcall+0x38/0x12c
> [    1.560886] kernel_init_freeable+0x148/0x1ec
> [    1.566972] kernel_init+0x10/0xfc
> [    1.572101] ret_from_fork+0x10/0x40
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Rhyland Klein <rklein@nvidia.com>

And maybe:
Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core")


> ---
> v2:
>  - Added cc stable
>  - changed return to -EAGAIN in case of use_cnt < 1
>  - Removed WARNING
>  - return value check added in additional patch:
>   "thermal: helpers: Check return value of get_temp"
> 
>  drivers/power/power_supply_core.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
> index 456987c88baa..bbd80631f31e 100644
> --- a/drivers/power/power_supply_core.c
> +++ b/drivers/power/power_supply_core.c
> @@ -561,11 +561,15 @@ static int power_supply_read_temp(struct thermal_zone_device *tzd,
>  {
>  	struct power_supply *psy;
>  	union power_supply_propval val;
> -	int ret;
> +	int ret = -EAGAIN;
>  
>  	WARN_ON(tzd == NULL);
> +
>  	psy = tzd->devdata;
> -	ret = psy->desc->get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);
> +
> +	if (atomic_read(&psy->use_cnt) > 0)
> +		ret = psy->desc->get_property(psy, POWER_SUPPLY_PROP_TEMP,
> +					      &val);

How about using just power_supply_get_property() and convert return
value to EAGAIN?

Anyway probably such check should be present also on other
get_property() calls, like thermal cooling path.

Best regards,
Krzysztof

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [RESEND PATCH v2] power_supply: power_supply_read_temp only if use_cnt > 0
  2016-06-07  7:23 ` Krzysztof Kozlowski
@ 2016-06-07 16:45   ` Rhyland Klein
  0 siblings, 0 replies; 3+ messages in thread
From: Rhyland Klein @ 2016-06-07 16:45 UTC (permalink / raw)
  To: Krzysztof Kozlowski, Sebastian Reichel, Dmitry Eremin-Solenikov,
	David Woodhouse
  Cc: linux-pm, linux-kernel, Jon Hunter, stable

On 6/7/2016 3:23 AM, Krzysztof Kozlowski wrote:
> On 06/06/2016 06:56 PM, Rhyland Klein wrote:
>> Add check to power_supply_read_temp() to only use the power_supply
>> get_property() callback if the use_cnt is > 0. The use_cnt will
>> be incremented at the end of __power_supply_register, so this will
>> block to case where get_property can be called before the supply
>> is fully registered. This fixes the issue show in the stack below:
>>
>> [    1.452598] power_supply_read_temp+0x78/0x80
>> [    1.458680] thermal_zone_get_temp+0x5c/0x11c
>> [    1.464765] thermal_zone_device_update+0x34/0xb4
>> [    1.471195] thermal_zone_device_register+0x87c/0x8cc
>> [    1.477974] __power_supply_register+0x364/0x424
>> [    1.484317] power_supply_register_no_ws+0x10/0x18
>> [    1.490833] bq27xxx_battery_setup+0x10c/0x164
>> [    1.497003] bq27xxx_battery_i2c_probe+0xd0/0x1b0
>> [    1.503435] i2c_device_probe+0x174/0x240
>> [    1.509172] driver_probe_device+0x1fc/0x29c
>> [    1.515167] __driver_attach+0xa4/0xa8
>> [    1.520643] bus_for_each_dev+0x58/0x98
>> [    1.526204] driver_attach+0x20/0x28
>> [    1.531505] bus_add_driver+0x1c8/0x22c
>> [    1.537067] driver_register+0x68/0x108
>> [    1.542630] i2c_register_driver+0x38/0x7c
>> [    1.548457] bq27xxx_battery_i2c_driver_init+0x18/0x20
>> [    1.555321] do_one_initcall+0x38/0x12c
>> [    1.560886] kernel_init_freeable+0x148/0x1ec
>> [    1.566972] kernel_init+0x10/0xfc
>> [    1.572101] ret_from_fork+0x10/0x40
>>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Rhyland Klein <rklein@nvidia.com>
> 
> And maybe:
> Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core")

Sure, I wasn't sure which commit this should *fix*, but that makes sense.

> 
> 
>> ---
>> v2:
>>  - Added cc stable
>>  - changed return to -EAGAIN in case of use_cnt < 1
>>  - Removed WARNING
>>  - return value check added in additional patch:
>>   "thermal: helpers: Check return value of get_temp"
>>
>>  drivers/power/power_supply_core.c | 8 ++++++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
>> index 456987c88baa..bbd80631f31e 100644
>> --- a/drivers/power/power_supply_core.c
>> +++ b/drivers/power/power_supply_core.c
>> @@ -561,11 +561,15 @@ static int power_supply_read_temp(struct thermal_zone_device *tzd,
>>  {
>>  	struct power_supply *psy;
>>  	union power_supply_propval val;
>> -	int ret;
>> +	int ret = -EAGAIN;
>>  
>>  	WARN_ON(tzd == NULL);
>> +
>>  	psy = tzd->devdata;
>> -	ret = psy->desc->get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);
>> +
>> +	if (atomic_read(&psy->use_cnt) > 0)
>> +		ret = psy->desc->get_property(psy, POWER_SUPPLY_PROP_TEMP,
>> +					      &val);
> 
> How about using just power_supply_get_property() and convert return
> value to EAGAIN?

I like that. I'll swap it over to use that.

> 
> Anyway probably such check should be present also on other
> get_property() calls, like thermal cooling path.

I'll look around and see what else I can find.

> 
> Best regards,
> Krzysztof
> 

-rhyland

-- 
nvpublic

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2016-06-07 16:46 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2016-06-06 16:56 [RESEND PATCH v2] power_supply: power_supply_read_temp only if use_cnt > 0 Rhyland Klein
2016-06-07  7:23 ` Krzysztof Kozlowski
2016-06-07 16:45   ` Rhyland Klein

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