[PATCH v4] power_supply: power_supply_read_temp only if use_cnt > 0

Rhyland Klein
2016-06-09T21:28:39Z

Change power_supply_read_temp() to use power_supply_get_property()
so that it will check the use_cnt and ensure it 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

Also make the same change to ps_get_max_charge_cntl_limit() and
ps_get_cur_chrage_cntl_limit() to be safe. Lastly, change the return
value of power_supply_get_property() to -EAGAIN from -ENODEV if
use_cnt <= 0.

Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core")
Cc: stable@vger.kernel.org
Signed-off-by: Rhyland Klein <rklein@nvidia.com>
---
v4:
- Fixed return check conditions
- Removed change to power_supply_get_property return code
- removed whitespace change

v3:
- Changed calls to ->get_property() to use common
power_supply_get_property()
- reworded description, added "Fixes" line
- Changed return value of power_supply_get_property() to -EAGAIN

v2:
- Added cc stable
- changed return to -EAGAIN in case of use_cnt < 1
- Removed WARNING
- return value check added in additional patch:
https://patchwork.kernel.org/patch/9158805/

drivers/power/power_supply_core.c | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index 456987c88baa..b13cd074c52a 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -565,11 +565,12 @@ static int power_supply_read_temp(struct thermal_zone_device *tzd,

WARN_ON(tzd == NULL);
psy = tzd->devdata;
- ret = psy->desc->get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);
+ ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);
+ if (ret)
+ return ret;

/* Convert tenths of degree Celsius to milli degree Celsius. */
- if (!ret)
- *temp = val.intval * 100;
+ *temp = val.intval * 100;

return ret;
}
@@ -612,10 +613,12 @@ static int ps_get_max_charge_cntl_limit(struct thermal_cooling_device *tcd,
int ret;

psy = tcd->devdata;
- ret = psy->desc->get_property(psy,
- POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX, &val);
- if (!ret)
- *state = val.intval;
+ ret = power_supply_get_property(psy,
+ POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX, &val);
+ if (ret)
+ return ret;
+
+ *state = val.intval;

return ret;
}
@@ -628,10 +631,12 @@ static int ps_get_cur_chrage_cntl_limit(struct thermal_cooling_device *tcd,
int ret;

psy = tcd->devdata;
- ret = psy->desc->get_property(psy,
- POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT, &val);
- if (!ret)
- *state = val.intval;
+ ret = power_supply_get_property(psy,
+ POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT, &val);
+ if (ret)
+ return ret;
+
+ *state = val.intval;

return ret;
}
--
1.9.1