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()`.
Commit 1c1f13a006ed ("power: supply: ab8500: Move to componentized
binding") introduced this issue during a refactorization. Fix this racy
use-after-free by making sure the IRQ is requested _after_ the
registration of the `power_supply` handle.
Fixes: 1c1f13a006ed ("power: supply: ab8500: Move to componentized binding")
Signed-off-by: Waqar Hameed <waqar.hameed@axis.com>
---
drivers/power/supply/ab8500_charger.c | 40 +++++++++++++--------------
1 file changed, 20 insertions(+), 20 deletions(-)
diff --git a/drivers/power/supply/ab8500_charger.c b/drivers/power/supply/ab8500_charger.c
index 5f4537766e5b9..1813fbdfa1c1f 100644
--- a/drivers/power/supply/ab8500_charger.c
+++ b/drivers/power/supply/ab8500_charger.c
@@ -3466,26 +3466,6 @@ static int ab8500_charger_probe(struct platform_device *pdev)
return ret;
}
- /* Request interrupts */
- for (i = 0; i < ARRAY_SIZE(ab8500_charger_irq); i++) {
- irq = platform_get_irq_byname(pdev, ab8500_charger_irq[i].name);
- if (irq < 0)
- return irq;
-
- ret = devm_request_threaded_irq(dev,
- irq, NULL, ab8500_charger_irq[i].isr,
- IRQF_SHARED | IRQF_NO_SUSPEND | IRQF_ONESHOT,
- ab8500_charger_irq[i].name, di);
-
- if (ret != 0) {
- dev_err(dev, "failed to request %s IRQ %d: %d\n"
- , ab8500_charger_irq[i].name, irq, ret);
- return ret;
- }
- dev_dbg(dev, "Requested %s IRQ %d: %d\n",
- ab8500_charger_irq[i].name, irq, ret);
- }
-
/* initialize lock */
spin_lock_init(&di->usb_state.usb_lock);
mutex_init(&di->usb_ipt_crnt_lock);
@@ -3614,6 +3594,26 @@ static int ab8500_charger_probe(struct platform_device *pdev)
return PTR_ERR(di->usb_chg.psy);
}
+ /* Request interrupts */
+ for (i = 0; i < ARRAY_SIZE(ab8500_charger_irq); i++) {
+ irq = platform_get_irq_byname(pdev, ab8500_charger_irq[i].name);
+ if (irq < 0)
+ return irq;
+
+ ret = devm_request_threaded_irq(dev,
+ irq, NULL, ab8500_charger_irq[i].isr,
+ IRQF_SHARED | IRQF_NO_SUSPEND | IRQF_ONESHOT,
+ ab8500_charger_irq[i].name, di);
+
+ if (ret != 0) {
+ dev_err(dev, "failed to request %s IRQ %d: %d\n"
+ , ab8500_charger_irq[i].name, irq, ret);
+ return ret;
+ }
+ dev_dbg(dev, "Requested %s IRQ %d: %d\n",
+ ab8500_charger_irq[i].name, irq, ret);
+ }
+
/*
* Check what battery we have, since we always have the USB
* psy, use that as a handle.
--
2.39.5