mirror of
https://github.com/FEX-Emu/linux.git
synced 2025-01-26 20:58:33 +00:00
e28ceeb10c
The timer handling in this driver is broken in several ways: - corkscrew_open() initializes and arms a timer before requesting the device interrupt. If the request fails the timer stays armed. A second call to corkscrew_open will unconditionally reinitialize the quued timer and arm it again. Also a immediate device removal will leave the timer queued because close() is not called (open() failed) and therefore nothing issues del_timer(). The reinitialization corrupts the link chain in the timer wheel hash bucket and causes a NULL pointer dereference when the timer wheel tries to operate on that hash bucket. Immediate device removal lets the link chain poke into freed and possibly reused memory. Solution: Arm the timer after the successful irq request. - corkscrew_close() uses del_timer() On close the timer is disarmed with del_timer() which lets the following code race against a concurrent timer expiry function. Solution: Use del_timer_sync() instead - corkscrew_close() calls del_timer() unconditionally del_timer() is invoked even if the timer was never initialized. This works by chance because the struct containing the timer is zeroed at allocation time. Solution: Move the setup of the timer into corkscrew_setup(). Reported-by: Matthew Whitehead <tedheadster@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: netdev@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>