Unknown
CVSS N/A
Overview
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: u_serial: Fix race condition in TTY wakeup
A race condition occurs when gs_start_io() calls either gs_start_rx() or
gs_start_tx(), as those functions briefly drop the port_lock for
usb_ep_queue(). This allows gs_close() and gserial_disconnect() to clear
port.tty and port_usb, respectively.
Use the null-safe TTY Port helper function to wake up TTY.
Example
CPU1: CPU2:
gserial_connect() // lock
gs_close() // await lock
gs_start_rx() // unlock
usb_ep_queue()
gs_close() // lock, reset port.tty and unlock
gs_start_rx() // lock
tty_wakeup() // NPE