From: Waqar Hameed Date: Sat, 20 Dec 2025 22:36:01 +0000 (+0100) Subject: power: supply: pm8916_lbc: Fix use-after-free in power_supply_changed() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b7508129978ae1e2ed9b0410396abc05def9c4eb;p=thirdparty%2Fkernel%2Flinux.git power: supply: pm8916_lbc: Fix use-after-free in power_supply_changed() 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: f8d7a3d21160 ("power: supply: Add driver for pm8916 lbc") Signed-off-by: Waqar Hameed Reviewed-by: Nikita Travkin Link: https://patch.msgid.link/64d8dd3675a4e59fa32c3e0ef451f12d1f7ed18f.1766268280.git.waqar.hameed@axis.com Signed-off-by: Sebastian Reichel --- diff --git a/drivers/power/supply/pm8916_lbc.c b/drivers/power/supply/pm8916_lbc.c index c74b75b1b2676..3ca717d84aade 100644 --- a/drivers/power/supply/pm8916_lbc.c +++ b/drivers/power/supply/pm8916_lbc.c @@ -274,15 +274,6 @@ static int pm8916_lbc_charger_probe(struct platform_device *pdev) return dev_err_probe(dev, -EINVAL, "Wrong amount of reg values: %d (4 expected)\n", len); - irq = platform_get_irq_byname(pdev, "usb_vbus"); - if (irq < 0) - return irq; - - ret = devm_request_threaded_irq(dev, irq, NULL, pm8916_lbc_charger_state_changed_irq, - IRQF_ONESHOT, "pm8916_lbc", chg); - if (ret) - return ret; - ret = device_property_read_u32_array(dev, "reg", chg->reg, len); if (ret) return ret; @@ -332,6 +323,15 @@ static int pm8916_lbc_charger_probe(struct platform_device *pdev) if (ret) return dev_err_probe(dev, ret, "Unable to get battery info\n"); + irq = platform_get_irq_byname(pdev, "usb_vbus"); + if (irq < 0) + return irq; + + ret = devm_request_threaded_irq(dev, irq, NULL, pm8916_lbc_charger_state_changed_irq, + IRQF_ONESHOT, "pm8916_lbc", chg); + if (ret) + return ret; + chg->edev = devm_extcon_dev_allocate(dev, pm8916_lbc_charger_cable); if (IS_ERR(chg->edev)) return PTR_ERR(chg->edev);