[PATCH 5.15 099/164] power: supply: bq25980: Fix use-after-free in power_supply_changed()

Sasha Levin
2026-02-28T18:16:29Z

From: Waqar Hameed <waqar.hameed@axis.com>

[ Upstream commit 5f0b1cb41906e86b64bf69f5ededb83b0d757c27 ]

Using the `devm_` variant for requesting IRQ _before_ the `devm_`
variant for allocating/registering the `power_supply` handle, means that
the `power_supply` handle will be deallocated/unregistered _before_ the
interrupt handler (since `devm_` naturally deallocates in reverse
allocation order). This means that during removal, there is a race
condition where an interrupt can fire just _after_ the `power_supply`
handle has been freed, *but* just _before_ the corresponding
unregistration of the IRQ handler has run.

This will lead to the IRQ handler calling `power_supply_changed()` with
a freed `power_supply` handle. Which usually crashes the system or
otherwise silently corrupts the memory...

Note that there is a similar situation which can also happen during
`probe()`; the possibility of an interrupt firing _before_ registering
the `power_supply` handle. This would then lead to the nasty situation
of using the `power_supply` handle *uninitialized* in
`power_supply_changed()`.

Fix this racy use-after-free by making sure the IRQ is requested _after_
the registration of the `power_supply` handle.

Fixes: 5069185fc18e ("power: supply: bq25980: Add support for the BQ259xx family")
Signed-off-by: Waqar Hameed <waqar.hameed@axis.com>
Link: https://patch.msgid.link/8763035cadb959e14787b3837f2d3db61f6e1c34.1766268280.git.waqar.hameed@axis.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/power/supply/bq25980_charger.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/power/supply/bq25980_charger.c b/drivers/power/supply/bq25980_charger.c
index 0008c229fd9c7..a93919c4ea275 100644
--- a/drivers/power/supply/bq25980_charger.c
+++ b/drivers/power/supply/bq25980_charger.c
@@ -1241,6 +1241,12 @@ static int bq25980_probe(struct i2c_client *client,
return ret;
}

+ ret = bq25980_power_supply_init(bq, dev);
+ if (ret) {
+ dev_err(dev, "Failed to register power supply\n");
+ return ret;
+ }
+
if (client->irq) {
ret = devm_request_threaded_irq(dev, client->irq, NULL,
bq25980_irq_handler_thread,
@@ -1251,12 +1257,6 @@ static int bq25980_probe(struct i2c_client *client,
return ret;
}

- ret = bq25980_power_supply_init(bq, dev);
- if (ret) {
- dev_err(dev, "Failed to register power supply\n");
- return ret;
- }
-
ret = bq25980_hw_init(bq);
if (ret) {
dev_err(dev, "Cannot initialize the chip.\n");
--
2.51.0