serial: 8250_dw: Fix deadlock in LCR workaround

Trying to write console output from within the serial console driver
while the port->lock is held causes recursive deadlock:

  CPU 0
spin_lock_irqsave(&port->lock)
printk()
  console_unlock()
    call_console_drivers()
      serial8250_console_write()
        spin_lock_irqsave(&port->lock)
** DEADLOCK **

The 8250_dw i/o accessors try to write a console error message if the
LCR workaround was unsuccessful. When the port->lock is already held
(eg., when called from serial8250_set_termios()), this deadlocks.

Make the error message a FIXME until a general solution is devised.

Cc: Tim Kryger <[email protected]>
Reported-by: Zhang Zhen <[email protected]>
Signed-off-by: Peter Hurley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

0 files changed, 0 insertions, 0 deletions