From 902b98b9df091669c791dd7c41727ffd37c28c47 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Sat, 15 Apr 2023 20:23:32 +0200 Subject: [PATCH] power: supply: bq27xxx: Fix bq27xxx_battery_update() race condition commit 5c34c0aef185dcd10881847b9ebf20046aa77cb4 upstream. bq27xxx_battery_update() assumes / requires that it is only run once, not multiple times at the same time. But there are 3 possible callers: 1. bq27xxx_battery_poll() delayed_work item handler 2. bq27xxx_battery_irq_handler_thread() I2C IRQ handler 3. bq27xxx_battery_setup() And there is no protection against these racing with each other, fix this race condition by making all callers take di->lock: - Rename bq27xxx_battery_update() to bq27xxx_battery_update_unlocked() - Add new bq27xxx_battery_update() which takes di->lock and then calls bq27xxx_battery_update_unlocked() - Make stale cache check code in bq27xxx_battery_get_property(), which already takes di->lock directly to check the jiffies, call bq27xxx_battery_update_unlocked() instead of messing with the delayed_work item - Make bq27xxx_battery_update_unlocked() mod the delayed-work item so that the next poll is delayed to poll_interval milliseconds after the last update independent of the source of the update Fixes: dd2dd2078771 ("bq27x00: Poll battery state") Signed-off-by: Hans de Goede Signed-off-by: Sebastian Reichel Signed-off-by: Greg Kroah-Hartman --- drivers/power/supply/bq27xxx_battery.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c index 8bf048fbd36a2..adde336e6d55c 100644 --- a/drivers/power/supply/bq27xxx_battery.c +++ b/drivers/power/supply/bq27xxx_battery.c @@ -1761,7 +1761,7 @@ static int bq27xxx_battery_read_health(struct bq27xxx_device_info *di) return POWER_SUPPLY_HEALTH_GOOD; } -void bq27xxx_battery_update(struct bq27xxx_device_info *di) +static void bq27xxx_battery_update_unlocked(struct bq27xxx_device_info *di) { struct bq27xxx_reg_cache cache = {0, }; bool has_singe_flag = di->opts & BQ27XXX_O_ZERO; @@ -1800,6 +1800,16 @@ void bq27xxx_battery_update(struct bq27xxx_device_info *di) di->cache = cache; di->last_update = jiffies; + + if (poll_interval > 0) + mod_delayed_work(system_wq, &di->work, poll_interval * HZ); +} + +void bq27xxx_battery_update(struct bq27xxx_device_info *di) +{ + mutex_lock(&di->lock); + bq27xxx_battery_update_unlocked(di); + mutex_unlock(&di->lock); } EXPORT_SYMBOL_GPL(bq27xxx_battery_update); @@ -1810,9 +1820,6 @@ static void bq27xxx_battery_poll(struct work_struct *work) work.work); bq27xxx_battery_update(di); - - if (poll_interval > 0) - schedule_delayed_work(&di->work, poll_interval * HZ); } static bool bq27xxx_battery_is_full(struct bq27xxx_device_info *di, int flags) @@ -1985,10 +1992,8 @@ static int bq27xxx_battery_get_property(struct power_supply *psy, struct bq27xxx_device_info *di = power_supply_get_drvdata(psy); mutex_lock(&di->lock); - if (time_is_before_jiffies(di->last_update + 5 * HZ)) { - cancel_delayed_work_sync(&di->work); - bq27xxx_battery_poll(&di->work.work); - } + if (time_is_before_jiffies(di->last_update + 5 * HZ)) + bq27xxx_battery_update_unlocked(di); mutex_unlock(&di->lock); if (psp != POWER_SUPPLY_PROP_PRESENT && di->cache.flags < 0) -- 2.39.5