This is a note to let you know that I've just added the patch titled
power: supply: bq27xxx: Fix poll_interval handling and races on remove
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
power-supply-bq27xxx-fix-poll_interval-handling-and-races-on-remove.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c00bc80462afc7963f449d7f21d896d2f629cacc Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@xxxxxxxxxx>
Date: Sat, 15 Apr 2023 20:23:34 +0200
Subject: power: supply: bq27xxx: Fix poll_interval handling and races on remove
From: Hans de Goede <hdegoede@xxxxxxxxxx>
commit c00bc80462afc7963f449d7f21d896d2f629cacc upstream.
Before this patch bq27xxx_battery_teardown() was setting poll_interval = 0
to avoid bq27xxx_battery_update() requeuing the delayed_work item.
There are 2 problems with this:
1. If the driver is unbound through sysfs, rather then the module being
rmmod-ed, this changes poll_interval unexpectedly
2. This is racy, after it being set poll_interval could be changed
before bq27xxx_battery_update() checks it through
/sys/module/bq27xxx_battery/parameters/poll_interval
Fix this by added a removed attribute to struct bq27xxx_device_info and
using that instead of setting poll_interval to 0.
There also is another poll_interval related race on remove(), writing
/sys/module/bq27xxx_battery/parameters/poll_interval will requeue
the delayed_work item for all devices on the bq27xxx_battery_devices
list and the device being removed was only removed from that list
after cancelling the delayed_work item.
Fix this by moving the removal from the bq27xxx_battery_devices list
to before cancelling the delayed_work item.
Fixes: 8cfaaa811894 ("bq27x00_battery: Fix OOPS caused by unregistring bq27x00 driver")
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/power/supply/bq27xxx_battery.c | 22 +++++++++-------------
include/linux/power/bq27xxx_battery.h | 1 +
2 files changed, 10 insertions(+), 13 deletions(-)
--- a/drivers/power/supply/bq27xxx_battery.c
+++ b/drivers/power/supply/bq27xxx_battery.c
@@ -1555,7 +1555,7 @@ static void bq27xxx_battery_update_unloc
di->last_update = jiffies;
- if (poll_interval > 0)
+ if (!di->removed && poll_interval > 0)
mod_delayed_work(system_wq, &di->work, poll_interval * HZ);
}
@@ -1870,22 +1870,18 @@ EXPORT_SYMBOL_GPL(bq27xxx_battery_setup)
void bq27xxx_battery_teardown(struct bq27xxx_device_info *di)
{
- /*
- * power_supply_unregister call bq27xxx_battery_get_property which
- * call bq27xxx_battery_poll.
- * Make sure that bq27xxx_battery_poll will not call
- * schedule_delayed_work again after unregister (which cause OOPS).
- */
- poll_interval = 0;
-
- cancel_delayed_work_sync(&di->work);
-
- power_supply_unregister(di->bat);
-
mutex_lock(&bq27xxx_list_lock);
list_del(&di->list);
mutex_unlock(&bq27xxx_list_lock);
+ /* Set removed to avoid bq27xxx_battery_update() re-queuing the work */
+ mutex_lock(&di->lock);
+ di->removed = true;
+ mutex_unlock(&di->lock);
+
+ cancel_delayed_work_sync(&di->work);
+
+ power_supply_unregister(di->bat);
mutex_destroy(&di->lock);
}
EXPORT_SYMBOL_GPL(bq27xxx_battery_teardown);
--- a/include/linux/power/bq27xxx_battery.h
+++ b/include/linux/power/bq27xxx_battery.h
@@ -61,6 +61,7 @@ struct bq27xxx_device_info {
struct bq27xxx_access_methods bus;
struct bq27xxx_reg_cache cache;
int charge_design_full;
+ bool removed;
unsigned long last_update;
struct delayed_work work;
struct power_supply *bat;
Patches currently in stable-queue which might be from hdegoede@xxxxxxxxxx are
queue-4.14/power-supply-leds-fix-blink-to-led-on-transition.patch
queue-4.14/power-supply-bq27xxx-fix-i2c-irq-race-on-remove.patch
queue-4.14/power-supply-bq27xxx-fix-bq27xxx_battery_update-race-condition.patch
queue-4.14/wifi-iwlwifi-dvm-fix-memcpy-detected-field-spanning-.patch
queue-4.14/power-supply-bq27xxx-fix-poll_interval-handling-and-races-on-remove.patch
