From: Waqar Hameed Date: Sat, 20 Dec 2025 22:36:01 +0000 (+0100) Subject: power: supply: pm8916_bms_vm: Fix use-after-free in power_supply_changed() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=62914959b35e9a1e29cc0f64cb8cfc5075a5366f;p=thirdparty%2Flinux.git power: supply: pm8916_bms_vm: 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: 098bce1838e0 ("power: supply: Add pm8916 VM-BMS support") Signed-off-by: Waqar Hameed Reviewed-by: Nikita Travkin Link: https://patch.msgid.link/2749c09ff81fcac87ae48147e216135450d8c067.1766268280.git.waqar.hameed@axis.com Signed-off-by: Sebastian Reichel --- diff --git a/drivers/power/supply/pm8916_bms_vm.c b/drivers/power/supply/pm8916_bms_vm.c index 5120be086e6ff..de5d571c03e21 100644 --- a/drivers/power/supply/pm8916_bms_vm.c +++ b/drivers/power/supply/pm8916_bms_vm.c @@ -167,15 +167,6 @@ static int pm8916_bms_vm_battery_probe(struct platform_device *pdev) if (ret < 0) return -EINVAL; - irq = platform_get_irq_byname(pdev, "fifo"); - if (irq < 0) - return irq; - - ret = devm_request_threaded_irq(dev, irq, NULL, pm8916_bms_vm_fifo_update_done_irq, - IRQF_ONESHOT, "pm8916_vm_bms", bat); - if (ret) - return ret; - ret = regmap_bulk_read(bat->regmap, bat->reg + PM8916_PERPH_TYPE, &tmp, 2); if (ret) goto comm_error; @@ -220,6 +211,15 @@ static int pm8916_bms_vm_battery_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, "fifo"); + if (irq < 0) + return irq; + + ret = devm_request_threaded_irq(dev, irq, NULL, pm8916_bms_vm_fifo_update_done_irq, + IRQF_ONESHOT, "pm8916_vm_bms", bat); + if (ret) + return ret; + platform_set_drvdata(pdev, bat); return 0;