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Deletion of subdevice will remove device properties associated to parent when they share the same firmware node after commit478573c93a(driver core: Don't leak secondary fwnode on device removal). This was observed with a driver adding subdevice that driver wasn't able to read device properties after rmmod/modprobe cycle. Consider the lifecycle of it: parent device registration ACPI_COMPANION_SET() device_add_properties() pset_copy_set() set_secondary_fwnode(dev, &p->fwnode) device_add() parent probe read device properties ACPI_COMPANION_SET(subdevice, ACPI_COMPANION(parent)) device_add(subdevice) parent remove device_del(subdevice) device_remove_properties() set_secondary_fwnode(dev, NULL); pset_free() Parent device will have its primary firmware node pointing to an ACPI node and secondary firmware node point to device properties. ACPI_COMPANION_SET() call in parent probe will set the subdevice's firmware node to point to the same 'struct fwnode_handle' and the associated secondary firmware node, i.e. the device properties as the parent. When subdevice is deleted in parent remove that will remove those device properties and attempt to read device properties in next parent probe call will fail. Fix this by tracking the owner device of device properties and delete them only when owner device is being deleted. Fixes:478573c93a(driver core: Don't leak secondary fwnode on device removal) Cc: 4.9+ <stable@vger.kernel.org> # 4.9+ Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.