概要

In the Linux kernel, the following vulnerability has been resolved:USB: core: Fix deadlock in usb_deauthorize_interface()Among the attribute file callback routines indrivers/usb/core/sysfs.c, the interface_authorized_store() function isthe only one which acquires a device lock on an ancestor device: Itcalls usb_deauthorize_interface(), which locks the interface s parentUSB device.The will lead to deadlock if another process already owns that lockand tries to remove the interface, whether through a configurationchange or because the device has been disconnected. As part of theremoval procedure, device_del() waits for all ongoing sysfs attributecallbacks to complete. But usb_deauthorize_interface() can t completeuntil the device lock has been released, and the lock won t bereleased until the removal has finished.The mechanism provided by sysfs to prevent this kind of deadlock isto use the sysfs_break_active_protection() function, which tells sysfsnot to wait for the attribute callback.Reported-and-tested by: Yue Sun <samsun1006219@gmail.com>Reported by: xingwei lee <xrivendell7@gmail.com>

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