acpi_bus_trim() stops removing devices, when acpi_bus_remove() return error number. But acpi_bus_remove() cannot return error number correctly. acpi_bus_remove() only return -EINVAL, when dev argument is NULL. Thus even if device cannot be removed correctly, acpi_bus_trim() ignores and continues to remove devices. acpi_bus_hot_remove_device() uses acpi_bus_trim() for removing devices. Therefore acpi_bus_hot_remove_device() can send "_EJ0" to firmware, even if the device is running on the system. In this case, the system cannot work well. Vasilis hit the bug at memory hotplug and reported it as follow: https://lkml.org/lkml/2012/9/26/318 So acpi_bus_trim() should check whether device was removed or not correctly. The patch adds error check into some functions to remove the device. Applying the patch, acpi_bus_trim() stops removing devices when failing to remove the device. But I think there is no impact with the exceptionof CPU and Memory hotplug path. Because other device also fails but the fail is an irregular case like device is NULL. v1->v2 - add a rollback for reinstalling a notify handler. Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx> --- drivers/acpi/scan.c | 21 ++++++++++++++++++--- drivers/base/dd.c | 22 +++++++++++++++++----- include/linux/device.h | 2 +- 3 files changed, 36 insertions(+), 9 deletions(-) Index: linux-3.6/drivers/acpi/scan.c =================================================================== --- linux-3.6.orig/drivers/acpi/scan.c 2012-10-11 18:31:40.189019503 +0900 +++ linux-3.6/drivers/acpi/scan.c 2012-10-11 18:42:35.669041641 +0900 @@ -445,18 +445,29 @@ static int acpi_device_remove(struct dev { struct acpi_device *acpi_dev = to_acpi_device(dev); struct acpi_driver *acpi_drv = acpi_dev->driver; + int ret; if (acpi_drv) { if (acpi_drv->ops.notify) acpi_device_remove_notify_handler(acpi_dev); - if (acpi_drv->ops.remove) - acpi_drv->ops.remove(acpi_dev, acpi_dev->removal_type); + if (acpi_drv->ops.remove) { + ret = acpi_drv->ops.remove(acpi_dev, + acpi_dev->removal_type); + if (ret) + goto rollback; + } } acpi_dev->driver = NULL; acpi_dev->driver_data = NULL; put_device(dev); return 0; + +rollback: + if (acpi_drv->ops.notify) + acpi_device_install_notify_handler(acpi_dev); + + return ret; } struct bus_type acpi_bus_type = { @@ -1226,11 +1237,15 @@ static int acpi_device_set_context(struc static int acpi_bus_remove(struct acpi_device *dev, int rmdevice) { + int ret; + if (!dev) return -EINVAL; dev->removal_type = ACPI_BUS_REMOVAL_EJECT; - device_release_driver(&dev->dev); + ret = device_release_driver(&dev->dev); + if (ret) + return ret; if (!rmdevice) return 0; Index: linux-3.6/drivers/base/dd.c =================================================================== --- linux-3.6.orig/drivers/base/dd.c 2012-10-11 18:31:40.191019505 +0900 +++ linux-3.6/drivers/base/dd.c 2012-10-11 18:31:46.873020548 +0900 @@ -475,9 +475,10 @@ EXPORT_SYMBOL_GPL(driver_attach); * __device_release_driver() must be called with @dev lock held. * When called for a USB interface, @dev->parent lock must be held as well. */ -static void __device_release_driver(struct device *dev) +static int __device_release_driver(struct device *dev) { struct device_driver *drv; + int ret = 0; drv = dev->driver; if (drv) { @@ -493,9 +494,11 @@ static void __device_release_driver(stru pm_runtime_put_sync(dev); if (dev->bus && dev->bus->remove) - dev->bus->remove(dev); + ret = dev->bus->remove(dev); else if (drv->remove) - drv->remove(dev); + ret = drv->remove(dev); + if (ret) + goto rollback; devres_release_all(dev); dev->driver = NULL; dev_set_drvdata(dev, NULL); @@ -506,6 +509,12 @@ static void __device_release_driver(stru dev); } + + return ret; + +rollback: + driver_sysfs_add(dev); + return ret; } /** @@ -515,16 +524,19 @@ static void __device_release_driver(stru * Manually detach device from driver. * When called for a USB interface, @dev->parent lock must be held. */ -void device_release_driver(struct device *dev) +int device_release_driver(struct device *dev) { + int ret; /* * If anyone calls device_release_driver() recursively from * within their ->remove callback for the same device, they * will deadlock right here. */ device_lock(dev); - __device_release_driver(dev); + ret = __device_release_driver(dev); device_unlock(dev); + + return ret; } EXPORT_SYMBOL_GPL(device_release_driver); Index: linux-3.6/include/linux/device.h =================================================================== --- linux-3.6.orig/include/linux/device.h 2012-10-11 18:31:40.194019508 +0900 +++ linux-3.6/include/linux/device.h 2012-10-11 18:31:46.881020556 +0900 @@ -834,7 +834,7 @@ static inline void *dev_get_platdata(con * for information on use. */ extern int __must_check device_bind_driver(struct device *dev); -extern void device_release_driver(struct device *dev); +extern int device_release_driver(struct device *dev); extern int __must_check device_attach(struct device *dev); extern int __must_check driver_attach(struct device_driver *drv); extern int __must_check device_reprobe(struct device *dev); -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
