power: supply: ab8500: Fix external_power_changed race

stable inclusion
from stable-v5.10.185
commit 9e9e150fa8a61cf1780aa680fcdffe24229e0c80
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8L5XP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9e9e150fa8a61cf1780aa680fcdffe24229e0c80



--------------------------------

[ Upstream commit a5299ce4 ]

ab8500_btemp_external_power_changed() dereferences di->btemp_psy,
which gets sets in ab8500_btemp_probe() like this:

        di->btemp_psy = devm_power_supply_register(dev, &ab8500_btemp_desc,
                                                   &psy_cfg);

As soon as devm_power_supply_register() has called device_add()
the external_power_changed callback can get called. So there is a window
where ab8500_btemp_external_power_changed() may get called while
di->btemp_psy has not been set yet leading to a NULL pointer dereference.

Fixing this is easy. The external_power_changed callback gets passed
the power_supply which will eventually get stored in di->btemp_psy,
so ab8500_btemp_external_power_changed() can simply directly use
the passed in psy argument which is always valid.

And the same applies to ab8500_fg_external_power_changed().

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>