4.15-stable review patch. If anyone has any objections, please let me know.
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From: Sebastian Andrzej Siewior bigeasy@linutronix.de
commit 44117a1d1732c513875d5a163f10d9adbe866c08 upstream.
setserial changes the IRQ via uart_set_info(). It invokes uart_shutdown() which free the current used IRQ and clear TTY_PORT_INITIALIZED. It will then update the IRQ number and invoke uart_startup() before returning to the caller leaving TTY_PORT_INITIALIZED cleared.
The next open will crash with | list_add double add: new=ffffffff839fcc98, prev=ffffffff839fcc98, next=ffffffff839fcc98. since the close from the IOCTL won't free the IRQ (and clean the list) due to the TTY_PORT_INITIALIZED check in uart_shutdown().
There is same pattern in uart_do_autoconfig() and I *think* it also needs to set TTY_PORT_INITIALIZED there. Is there a reason why uart_startup() does not set the flag by itself after the IRQ has been acquired (since it is cleared in uart_shutdown)?
Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/tty/serial/serial_core.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -974,6 +974,8 @@ static int uart_set_info(struct tty_stru } } else { retval = uart_startup(tty, state, 1); + if (retval == 0) + tty_port_set_initialized(port, true); if (retval > 0) retval = 0; }