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authorKrzysztof Kozlowski <k.kozlowski@samsung.com>2015-05-19 09:13:01 +0200
committerSebastian Reichel <sre@kernel.org>2015-05-21 15:40:54 +0200
commit8e59c7f23410d5ca6b350a178b861a3d68c49edf (patch)
tree3e26099e1e90a2112c467a9df7b1e1e4224ee398 /crypto/md5.c
parentLinux 4.1-rc4 (diff)
downloadlinux-8e59c7f23410d5ca6b350a178b861a3d68c49edf.tar.xz
linux-8e59c7f23410d5ca6b350a178b861a3d68c49edf.zip
power_supply: Fix NULL pointer dereference during bq27x00_battery probe
Power supply is often registered during probe of a driver. The power_supply_register() returns pointer to newly allocated structure as return value. However before returning the power_supply_register() calls back the get_property() method provided by the driver through uevent. In that time the driver probe is still in progress and driver did not assigned pointer to power supply to its local variables. This leads to NULL pointer dereference from get_property() function. Starting from bq27x00_battery_probe(): di->bat = power_supply_register() device_add() kobject_uevent() power_supply_uevent() power_supply_show_property() power_supply_get_property() bq27x00_battery_get_property() dereference of (di->bat) which is NULL here The first uevent of power supply (the one coming from device creation) should not call back to the driver. To prevent that from happening, increment the atomic use counter at the end of power_supply_register(). This means that power_supply_get_property() will return -ENODEV. IMPORTANT: The patch has impact on this first uevent sent from power supply because it will not contain properties from power supply. The uevent with properties will be sent later after indicating that power supply has changed. This also has a race now, but will be fixed in other patches. Reported-by: H. Nikolaus Schaller <hns@goldelico.com> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core") Tested-By: Dr. H. Nikolaus Schaller <hns@goldelico.com> Signed-off-by: Sebastian Reichel <sre@kernel.org>
Diffstat (limited to 'crypto/md5.c')
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