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serial: core: mark port as initialized after successful IRQ change

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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>
This commit is contained in:
Sebastian Andrzej Siewior 2018-01-11 18:57:26 +01:00 committed by Greg Kroah-Hartman
parent 7ee69102db
commit 44117a1d17
1 changed files with 2 additions and 0 deletions
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2
drivers/tty/serial/serial_core.c
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@ -974,6 +974,8 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
}
} else {
retval = uart_startup(tty, state, 1);
if (retval == 0)
tty_port_set_initialized(port, true);
if (retval > 0)
retval = 0;
}