Comment # 1 on bug 1201384 from Jiri Slaby

tty_port_block_til_ready+0x124 -> drivers/tty/tty_port.c:557
tty_port_open+0xc8 -> drivers/tty/tty_port.c:773
uart_open+0x28 -> drivers/tty/serial/serial_core.c:1773
tty_open+0x140 -> drivers/tty/tty_io.c:2153

I wonder why it didn't go via tty_reopen()... Is this new?