On Thu, 2007-09-27 at 11:30 +0800, Zhang Rui wrote: > Hi, all, > > I found a bug that linux/acpi may execute notify handler that > has been removed. > > When a system notify(0~0x7f) is received, linux/acpi will > first invoke the generic system notify handler (acpi_bus_notify) > and then invoke the per-device notify handler if present. > > In my case, I add some code in acpi_bus_notify for battery > hotplug support, so that the generic system notify handler will > remove the battery device, including the per-device notify handler > acpi_battery_notify() when receiving notification > ACPI_NOTIFY_EJECT_REQUEST. > But linux/acpi invokes the per-device notify handler soon and > this breaks the system. > > Further more, device hot-removal is not the only case to encounter > this bug. For example, linux/acpi receives a notification and adds it > in the workqueue, and then the driver(notify handler) is removed > before kacpid_notify invoke it... For the non-hotplug case, adding a flush work queue just after notify handler is removed should be ok.
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