4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -965,6 +965,8 @@ 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;
}